Awhile back I was walking along a beach when I came upon a series of heaped rocks stacked on top of each other. In English we can refer to these man-made piles of stones by the Gaelic term, cairn. In this instance, many of these rock stacking were the standard vertical stacking of flat stones from largest to smallest, evoking simple balance and zen. A few were dramatic constructions where larger rocks were sitting precariously atop at odd, gravity-defying angles.

Rock stacking is prehistoric activity and likely dates back to earliest days of humanity. Often built as a trail marker, landmark or memorial, rock stacking or rock balancing has become a popular form of relaxing, meditative play today. Rock stacking may not quite be as evocative or prestigious as other forms of artistic creation, but it definitely checks all the box of what we might call artistic creation: intentional, beautiful, skillful, temporal, expression, imaginative.

I’ll confess that my initial wonder at these these balanced rocks was broken by a mischievous, almost instinctive desire to topple them. To uncreate these creations. Destruction it could be argued is as creative, though in my case it was some form of Schadenfreude as I was merely seeking satisfaction in destruction for destruction.

On that occassion I was able to hold back my destructive tendency and simply enjoy the tranquil waves at sunset flanking these Mexican beach cains. Yet these strangely assembled rock stackings got me thinking:

Why do we create? And, whether it’s a life, a pill of stones or something else, what does the passage of time mean to the artistic creations we leave behind?

I recently turned 40 years old. Each birthday offers a kind of check-in point, a moment to pause and reflection. I’m a strong believer in time-based reflections, especially weekly reviews and year-in-reviews too. These kinds of reflections invite introspection, accountablity and goal setting.

Unlike other birthdays, the transition from one decade to the next, like turning 40, might be called a milestone birthday and calls at us to ponder one’s life and meaning a bit more than usual.

In On Turning 30: How have I spent my days?, I noted that I was staying in Corfu, Greece at the time. My note carries a lot of positivity, even though I do recall (and left unsaid in the post) a certain doubt in me then too. At 30 I was feeling a certain degree of gratitude and hope for the years ahead. But I was pretty uncertain about what was next.

In retrospect, it’s interesting to see how my 30-year old self was thinking and reflecting in terms of measurables, yardsticks and even tracking. As a reader of this blog is aware, self-tracking, quantified self and tracking tech have become a core habit in my life, a topic I’ve written extensively on and a major component of my personal and professional work too. I’ve written over 90 blog posts on tracking alone in last 10 years. I’ve recorded hundreds of running miles; time tracked over 25,000 hours of computer, project and device time; and quantified dozens of other productivity, creative and health metrics over time.

I firmly believe that a well-and-meaningfully tracked and tech-mediated life is one worth living. I also think positive human and society change is possible based on both behavior change and enabling choice towards enacting our intentions for a better self, world and future. Moreover, if selves (including our own) and societies are historical cultural artifacts, then they can change, evolve and transform.

In this post, I want to look back and reflect on my last decade, ponder my future days ahead and think about my life and human life in general as a form of artistic (cultural) creation.

Let’s start with two simple questions first: Who have I become? And what have I done in that last 3650 odd days?

My Last 10 Years: Who have I become?

At the end of a year, on a birthday or even upon death, we often get asked and ask ourselves: What have we done or achieved over time? What do we have to show for our time on this planet?

While acheivements are definitely a way to measure a life (more on this later), I think such questions skip over something more profound and more meaningful, namely the question of who we become? And to extend this further, who we are in the process of becoming?

In spite of the “Parmenidean dilemma” from ancient Greek Philosophy arguing that change in an illusion and underlying everything is a changeless reality, numerous philosopher, poets, thinkers and even religious figures point to life, reality and our world as a process of constant change. A permenant identity is an illusion, as David Hume pointed out. Our world is one of constant change. Ancient Greek philosopher Heraclitus allegedly once wrote:

“No man ever steps in the same river twice. For it’s not the same river and he’s not the same man.”

Put another way, change is the default state.

Language and convention tend to point us towards a “who are you” framing of self and reality, but such a state of being from Buddha and David Hume to modern day physics and neurobiology have largely been debunked. We are a becoming, forever-becoming, never-there. (I’ll leave aside religion and belief-based notions of an eternal, non-material separate state like Heaven or Nirvana and related concepts as essentially non-scientific and non-irrefutable in such worldviews.)

In spite of such a “metaphysics” of constant change and becoming, we retain a unitary sense of self and life. How is this possible? How, in spite of this state of contstant change, do we as a self and as experiencers of our world still feel experience things (including our self) as unitary and as same-as-yesterday-ness?

A full articulation of such ideas is beyond this post, but I believe this is partially based on our storytelling nature and the narrative unity such self-stories provide. Narrative unity is one component that gives us meaning and an orientation. It’s this meaning-creating capacities that gives change a certain experiential and conceptual permenance.

Besides social commitments and certain ethical ideals (like authenticity), I’ve long held learning and growth to be one of the most important components of an authentic, meaningful, flourishing and inspiring life for me and, I’d argue, for most human beings. Over the past two decades from my early 20s to now, I’ve learned many, many things and up-skilled in various ways. While I’m hardly a true expert in all of these, I have gained certain mastery and abilities. I hope to retain this pursue of learning in the year ahead as I believe skill building and cultivating mental models expands my knowledge and perceptual spheres.

Here’s a short list of some major learnings and becomings (with links to some related blog posts):


  • Learned Philosophy inc Phenomenology = Philosopher Mark
  • Learned and Mastered French (Language) = French Mark
  • Learned to teach = Teacher Mark
  • Learned basic coding and mastered Drupal/Web Development = Dev / Drupal / Engineering Mark
  • Learned and Master Chinese (Language) = Chinese Mark


  • Learned about startups, VC and business building = Startup Mark
  • Learned Spanish (Language) = El Chingro, aka Spanish Mark
  • Learned about scuba diving and oceanography = Diving Mark
  • Learned Python, Data Science, Data Visualization and even ML/AI = Data Science Mark
  • Learned Product Management and UX Design = “Head of Product” Mark
  • Learned about running and training to run = Runner Mark or Healthy Mark
  • Learned UX, UI and Graphic Design, prototyping, User Research = UX Designer Mark
  • Learned Digital Marketing and Growth Hacking = Growth Hacker or Marketing Mark
  • Learned music making and music production = Music Mark, aka Stellar Mammals

Even to me, this is a pretty long-winded list and perhaps reveals a certain dilettantism and wunderlust. I have lived in situations where my work hours were much less than 40 hours, I take a long-range view towards personal development, and as such I have been able to fuel a constant journey of growth.

Admittedly, when I meet someone new, I’ll often just pick one or two labels to introduce myself and include something about where I’m from and places I’ve lived. It’s convenient and polite to make yourself relatable in small pieces, but within each of us is an infite world of possibility and varied human experiences.

We can evolve and change in incredible ways. Seeing this list of my own learning’s and becoming’s is a strong reminder of such how much we can learn and grow in a few years. Many of these skills and identies were built up in small steps and 10 years ago I couldn’t have imagined who I am now. 20 years ago I couldn’t have thought of myself as a multilingual polyglot either. I can hardly imagine what’s ahead either, especially with these new tools of awesomeness called Machine Learning and Generative AI.

Besides these selves, labels or identities, I’ve grown in certain core behaviorial and cognitive sense too. I’m better organized, more learned and learning, more creative and have a higher rate of productive creative output too. These are not attributes I was born with, though I did inherit a certain propensity towards being organized. I could even argue that these productive and learning skills are the bedrock upon which I’ve cultivated skills and built roles for jobs and creative doings.

What are some of the habits and skills I’ve cultivated and become in recent years?

As a rather obcessive and dedicated self-tracker with many streams of data on my health, life and doings, I’d argue that self-tracking has been incredibly supportive of the life I have wanted to life. It’s changed my behavior. It’s helped me become more aware and attentive, improved my focus and increased flow or “being in the zone”. I track many different arenas of my life.

Personally one of the biggest (and earliest) behavior changes I took on was a form of personal productivity management. Inspired by David Allen’s Getting Things Done book and productivity philosophy I’ve built habits and mental models for managing my goals, projects, tasks, and, of course, time. Our brains have limited cognitive capacity and memory too, so an organizational system enables you give your brain a rest at remembering and organizing and instead focus on a singular doing. One of the simplest “tricks” is to simply ask yourself to define the next best task on a project or challenge, then simply do it. Rinse and repeat.

Time tracking is arguably one of my most central habits and practices. In my case, I use time tracking in combination with weekly goal setting to commit, prioritize and make progress on what I care about. This might be ensuring I get enough sleep and exercise, learn constantly, take notes and journal regularly or carve out consistent time for my professional and creative pursuits. When I start my time tracker, I’ve set my intention and attention for a period of time. Later when I look at my logs for myself or for my invoices, I can see exactly where my time went. Over time, this kind of intentional investment of focus and flow in my best-fit opportunities have driven both incremental progress and end-game acheivements.

To share just one example in a bit more detail, music (specifically music production and music making) has emerged as one of my main personal creative hobbies in the last two or three years. I have little to no background in music. I’ve had no teachers or structured help during this journey either. Yet, I’ve already released three music albums encompassing 30 tracks of nearly 90 minutes of music. A few tracks have even garnered a thousands of listens on Spotify.

For any venture, the time and effort you put is a huge component of determing the output and outcome you acheive. When it comes to music making, each week I strive to put consistent time into my music making. The specific allotment of my music time varies according to my goals, skill building needs and projects I’m pursuing. Early on in my music learning journey, I had to dedicate a lot of time to skill-building and exploring, but since then, having those skills have made it easier and easier to just show up and get into flow making music and songs.

Additionally, I do my best to avoid “pseudo-studying entertainment” trap of watching YouTube videos of others making music or talking about gear, rather than showing up and using what gear I have to start mkaing my own beats and song.

As my baseline music writing and music production improved I carved out time to organizing and finishing music. Each of these stages required a certain time input and pursuing appropriate and enabled goals and challenges. There was no singular step to get there but a series of growth-oriented, momentum-building steps over time on the path to progress and ultimately acheivement.

Music making is just one of example of several that I have applied to learning data science with python, UX and PM skills for product development, and digital marketing. I spend time early on reading and learning, then I find just-hard-enough challenges to apply those learnings via practical skills. This overall music approach is similar to writing and the host of professional tasks I take on as a product builder, marketer, manager, and entrepreneur. I set and review goals, define next tasks in those projects and then carve out time in my schedule to pursue them. I’ve come to develop what might be called an “organized mind.”

In view of how nonlinear and personalized a creative project like music making is, I take advantage of journaling and reflection as well. Each project or skill has a project log note where I capture periodic check-in’s and reflections, note goals and TODOs and just keep everything important in one place. Writing is a great way to express feelings and verbalize doubts and discoveries along the way.

My organized mind is built on various habits and techniques (i.e. defining next best actions, daily task management and weekly reviews) in combination with supportive technologies (i.e. time tracking, task management and note taking). One aspect of this is what I call the Plain Text Life, which is how I take notes, learn, write and plan creative and learning projects over time.

Recent advances in generative AI, especially LLMs and ChatGPT, have gotten me thinking about how I might use and revamp my writing and knowledge management systems through a tighter integration with AI. In the last 6 months, I even started journaling with AI and I predict these “technologies of self” will increasingly play a signficiant role in how we see ourselves and think creatively and critically. When it comes to art and creative work (which is largely what I do even for coding and product development), I can leverage AI to help me deal with self-doubt and other emotions along the way. Having an AI journaling companion enables me navigate challenging moments reflectively, get feedback and advice and “integrate” those into my own narrative, self-understanding and journey too.

I’ll admit that over last 10 or 15 years, I’ve spent substantial time developing my skills, habits and mental models and honing my technology usage towards my own brand or “style” of personal creative productivity. One other major and defining change point for me was learning how to learn, which was a free online course about how our brains learn and how we can instill habits and practices to learn more effectively. It was a game-changer for me. Similarly a deeper understanding of the science of flow has changed how I operate too, leading me to develop a better work practices and prioritize areas that trigger such immersive experiences found in deep work, problem-solving, collaboration, sports or other creative challenges. While everyone journey is unique, I believe a stopover at how to learn, how to get into flow and finding your purpose are key.

Throughout this journey of my own personal development, I’ve done by best to externalize my learning over time. Along with talking at events and conferences, my blog writing are a testement to the topics and skills I’ve built up over time.

I currently maintain several core habits:



I’ll admit that it took a good deal of time and resource investment learning about these areas and cultivating these habits and routines. There were some false starts on things that didn’t work for me and areas that took several tries to turn into routines. Now that I have largely settled in on my core habits and behaviors, I obcessively avoid switching my core organizational “tech,” since switching tools or approaches can be costly and waste a lot of time. How I spend my time does vary signficiantly over the last 10 years. This become apparent in my various year in review time logs. I strive to spend my time intentionally and maximize joy, curiousity and flow.

So what has been the products and achievements of this process?

My Last 3650 Days: Themes? How do you measure a life?

As a guy with a lot of tracking and quantified self data, I’ll confess that life shouldn’t be about measuring and collecting data; it should be about living fully, intentionally and meaningfully. Tracking, especially time tracking, are the guardrails and the compass heading during your pursuit.

First off, the last 10 years have been an amazing adventure and heck of a lot of fun. Again my ability to predict a life of doing beyond a few years is limited. I can often intuit a general next step but beyond a year or two is anyone’s guess. I continue to believe in pursuing short-term quests based on a longer-term vision or purpose or mission. This is my best recipe for personal progres and “success.”

So, what were some of the chapter headings over the last 10 years?

  • Computer Time: I spent a lot of time on my computer, a bit less on my phone and tablet. I still think creator computer usage is preferable to most other digital device doings. That said, in view of how much time I put on my comptuer, it is still strange to think of or identify myself as a hybrid being of self-machine, computer-man.
  • Startup Events: As regional manager and growth guy for Techstars and Startup Weekend in Great China, I organized, attended and fascilitated various action-based networking events. New connections were made, teams were formed, businesses were pitched, tried, failed and succeed too. Posts and notes on startup communities in China. Personally I’m most proud of the 3 Startup Next programs I got off the ground in Shanghai, Hong Kong and Taipei. I took a long break from startup event-ing until 2020 when I ended up co-directing Startup Next spinoff, Startup Boost in Los Angeles for 3 cohorts. I still enjoy hackathons as an action-based way to network and build stuff.
  • Blog Writings: My output and input into writing has varied a lot over the years but I’m happy to say I managed to write and publish 178 blog posts on during last decade. I also have one long book manuscript unpublished (on science of goals) and two early partially finished book drafts (one fiction, another nonfiction). In a world of trade-offs, I still regret not finishing nor publishing one of these book projects.
  • Things created, released, and shared: Product builder is definitely a core identity and mission for me. As a high-schooler it was simple HTML sites for corporate companies. Over last 15 years I’ve become a Drupal and PHP/javascript programmer and built many sites and online services. A few that I’m proud of include QS (Quantified Self) Ledger, an open source project for personal data aggregation and data visualization for self-tracking data; Biomarker Tracker DB and early biomarker tracking app;, an iOS and Android app to track photo-taking and craft visual data stories about a life in photos; and recently developing a consumer and clinical portal for the epigenetic nonprofit company Clock Foundation. Check out my products page for more info.
  • Music: Under the monkier of Stellar Mammals, I’ve released 30 songs including one EP and two full-length albums, spanning about 90 minutes of concentration and focus music.
  • Jobs: I’ve had a pretty eclectic working history. I continue to engage in a range of software related services as an active software engineer, head of product, UX designer and digital marketer. Mostly I’m just trying to help interesting and awesome products and services find my users and deliver greater value to their customers. I’m a Dev + UX Creative who loves designing and building data-centric products for health, well-being and general awesomeness.
  • How about languages? My Chinese and Spanish both improved signficantly and I got to try several hacking language trials (another creative side hustle) with Vietnamese, Korean, Thai and Burmese. My most successful for a short-term hack proved to be Burmese which you can read about in this case study / travelogue.
  • What about travels? For someone who defined himself by living abroad, ironically the last 3 or 4 years have been defined by not traveling due to COVID-19, lockdowns and travel restrictions. I ended up back in United States, based in Venice Beach, California. That said, over last several years, I’ve gotten to visit and live in an amazing collection of beautiful places and gone on some wonderful trips. I bought a house in China and spend nearly 3 years based out of Qingchengshan. I spent significant time in Colombia and Guatamala. I scuba dived (and even free dived) across the world including in Thailand, Mexico, Malaysia, Japan, Australia and even Taiwan. I had wonderful trips and stays in Singapore, France, Australia, and Sweden. I got to see some wonderful place in the US too, including Salton Sea, Channel Islands, Lake Powell Area, Yosemite, and Lake Tahoe. I just wish I had more friends in one place. My only regret is that you can only live one place at a time.
  • What about health and wellness? My body has changed alot in last decade. Unlike 10 years ago I am a much healthier being now. I run and exercise regularly. I have completed several marathons, half marathons and long hikes. I have better eating and health routines. I’m definitely more “tracked” than ever, including epigenetic age tests.
  • Biohacker / Quantified Self Life: While I don’t quite think my intentions and work around the quantified self have quite panned out the ways I had hoped, the journey has been amazing. For several years, I tried to track my life and develop integrations and tools to benefit a tracked life. You can read my archive of writings under Tracking Everything, a still on-going blog services explore intersection of technologies for data collection and methods for data-driven living. I coded and released an open source project (QS Ledger) for myself and others in the pursuit of a data-driven, quantified self life. I have developed a pretty unique way of measuring my own life. It is highly personalized and supportive of my data-driven yet value-centered approach to living creatively and expansively with technology.

Conclusion: What’s next?

This long winded bit of writing and reflection was penned from Venice, California. So, let’s end with a prospective question: What’s next?

If I had to pick a few personas for my next 10 years it would be:

  • Product Builder
  • Data-Driven Enabler (Both for Biology and for Selves)
  • Reflective Learner (including but not limited to technology, big ideas from philosophy and science, and, of course, thinking and creating skills)
  • Creative Doer, including but not limited to writing, music, video, and other visual arts
  • Philosopher-Thinker

This is the intersection points of my purpose (for now). A lot can change in 10 years and I may very well be doing something quite different from these. I intend to remain focused on product and technologies that enable selves, improve society and transform our health and biology.

I currently work in biotech space for a longevity research group (Clock Foundation / and also consult and mentor a few other startups and early stage products. Founded by Steve Horvath, The Clock Foundation is quantifying and measuring aging using epigenetic changes in our DNA. We have been involved in a lot of anti-aging studies and clinical trials.

The core mission of the Clock Foundation is extending human lifespan using accessible and affordable interventions. We (as humans) still have not cured aging or ended death, but I think many of the biological puzzles are starting to provide actionable and viable paths to extending how long we might potentially live. Personally, I believe death is a biological imperfection we can and will solve. Vitality and cognitive and performance enhancement are part of the human journey. Ending death or enabling signficant life extension might not happen in my life or at all. It might not be accessible or affordable for most either. Yet even if it’s simply a new data point to help us understand our biological nature, I believe it’s a worthy mission too.

My healthy habits should help me live a long, vital life. I may even get lucky and unlock a few extra years or decades. But let’s assume I live to at least 80. That means at my current age of 40, I have roughly 14,610 days left to live. That’s obvious a big number that is difficult to relate to. It is by no means infinite yet it remains conceptually large and expansive.

As I put it upon turning 30, time spent is time you can’t ever buy back. You can’t save time and use it later. Put another way, even if I do manage to live longer than expected, maybe beyond 80 and into my 100s, days, hours and minutes are largely all that count. You only live in the now. Extending our healthspan and lifespan doesn’t replace the grains of sand lost and wasted not living in the now.

In my case, I’m excited to continue to learn, grow, create and dream. There is more art to be tried, music to be made and joy to be experienced. I think humanity’s intersection with technologies (especially AI) offers me and all of us a new empowering creative platform for what’s ahead. I’m excited to help imagine it and build it.

Here’s to turning 40!

NOTE: The photos above are from my Venice Beach and Venice Canals in California as well as trips to Guatamala and Yosemite.

AIDA (AI Disclosure Acknowledgement): The following written content was created and written entirely by me (Mark Koester). I did not use any AI in the ideation, writing, and editing process.