The takeaways at the very bottom of the page are valuable:

> Overall, having spent a significant amount of time building this project, scaling it up to the size it’s at now, as well as analysing the data, the main conclusion is that it is not worth building your own solution, and investing this much time. When I first started building this project 3 years ago, I expected to learn way more surprising and interesting facts. There were some, and it’s super interesting to look through those graphs, however retrospectively, it did not justify the hundreds of hours I invested in this project.

The whole "quantified self" movement might be more about OCD and perfectionism than anything else.

/edit: quantified, not qualified

A counter example:

I've been wearing an Apple Watch for close to 10 years. I've tracked my weight as well along those years but nothing crazy like OP. The Apple watch tracked plenty.

I had some strange symptoms and two doctors insisted I had a weak heart and potential heart failure. This was shocking! Turns out I do have a really "weak" rhythm, but heart failure is when your heart is progressively getting worse in it's pumping. I don't even remember which metric he looked at in my Apple health - but basically my heart has always been this way. A doctor looking at a single data point might think I have abnormally low blood pressure/heart rate, but if I've had this for 10 years with no change, the medical assessment is very different - it means nothing. Sometimes boring data is exactly what you need. For this reason, I will probably always wear an Apple watch (or equivalent) moving forward.

Data can feel useless for 10 years until one day it becomes critical. The benefit is spiky and uneven.

I had a similar epiphany a few years back when I started wearing a step-tracker/sleep monitor.

It was kinda interesting to see how many times I woke up, or track hours, but to be honest I realised after a few months that when my tracker said "You had good sleep", or "You had bad sleep" I was already aware - I woke up smiling, or grumpy depending on how I'd done.

I didn't ever look at the data and think "I want to go to bed now to catch up on the four hours I missed yesterday". I continued to have mostly consistent hours, but if I was doing something interesting I'd stay awake, and if I was tired I'd go to bed earlier naturally. The graphs and data wasn't providing anything of value, or encouraging me to change my behaviour in any significant way.

> it did not justify the hundreds of hours I invested in this project.

I agree with this but minimizing the cost changes the ROI.

Personally, I've discovered useful insights tracking various life metrics. But I also found quickly diminishing returns after a few weeks or months -- if an association isn't obvious within that timeframe it's either too much effort to isolate or too slow or small to matter.

At various points I've tracked calories, macronutrients, weight, allergens, supplements, sleep, exercise volume, exercise timing, nighttime screen use, spending/budget, air quality, and mood. Now I know what kind of cooking wrecks the air quality in my house, what foods I don't digest well, what various protein/carb/fat ratios look like on my plate, how much effort it takes to improve fitness, that exercise in the morning or early afternoon improves my sleep while exercise in the evening harms it, and that any alcohol or caffeine wreck my sleep while screens at night have no measurable effect. But once I understand the associations I can alter my behavior and move on.

> The whole "quantified self" movement might be more about OCD and perfectionism than anything else.

I would agree that continuing to track metrics every day long after they've stopped yielding new insights is often compulsive behavior. But I think that's an argument for time-boxing experiments, not necessarily avoiding them altogether.

I never spent as much time as OP on this but I did collect a lot of data during peak quantified self. I liked having automatic data collection and being able to see trends, for example. I stopped because of a few issues, not related to time:

* Hardware companies went out of business, stopped supporting devices, etc. It became obvious that there was no long term commitment to make good quality hardware that lasted a long time.

* Many devices and/or data collection was consolidated big, data hungry companies Google and Apple. Competitors have similar anti-consumer uses of data. I don't want any of these companies to have my data.

* Related to the last one, limited to no offline or local only data collection.

It is very hard to gather most of this data with off the shelf hardware and keep your data private.

I kinda disagree. Doing something about open questions which are bothering you can be valuable in itself, even if the result of the process is useless in the end. And usually you are also learning some valuable things along the way, or just push your life into a necessary direction. That isn't related to OCD or perfectionism, it's just gaining more control and insight about some aspects of your life.

You're equating two different things here: "building a custom web application" with "quantified self". These are two entirely different things.

Felix's statement isn't a condemnation of quantified self. I think that sometimes, when you're applying algorithms that aren't well-studied, you get pointless or bogus data. I feel much this way about sleep tracking algorithms from the likes of Apple and Whoop. Vitals, too, although it seems remarkably good at detecting when I'm about to get sick.

As a person in the older demographic of HN, having an Apple Watch quietly collect useful data over years and store it in a database has been immensely useful in helping resolve medical issues.

I used to really be into QS, and if I'm training for a marathon, I'm still studying graphs and drawing conclusions. I'm still into QS, but now I just silently log data to Apple Health and use it for medical histories or to identify certain trends (vo2max, cardio fitness, blood pressure, etc) a couple times a year.

For me it's about managing ADHD-like (never diagnosed, and I don't care to assume) patterns, coupled with self-accountability. I have a self-improving dashboard (it kicks off Claude to propose additions based my positive/negative feedback on past attempts, and then builds them) that feels quite helpful. E.g. one of the things it added was fitbit integration that shoves my step count and resting heart rate in my face every day, and it's helped me drive my step count back up towards where I want it to be.

I do think it's not worth spending a whole lot of time on, though - hence why the first thing I did was add that mechanism to have Claude build it for me, with me mostly glancing at a plan and saying yes/no. It's the perfect thing to vibe-code - if it breaks, I revert a commit and it doesn't matter because nobody depends on it but me.

I have built a much more limited version of this that combines my journals, sketches, photos, geolocation etc. I found it useful for noticing patterns in my behaviour and in my irrationality. Journaling helped the most, because recording my feelings means acknowledging them and reviewing them.

Above all, it's just interesting. I enjoy reading about the day-by-day progression of a crush or my brutally honest feelings about a trip that produced stunning pictures. It weaves nuance into my history.

Agreed, I have tendency to do this to “fix” something in my life, after doing it for 2 weeks I already know, just the consciously pay attention to something even without recording make it very obvious what’s going on.

> however retrospectively, it did not justify the hundreds of hours I invested in this project.

Trying to extrapolate this conclusion to the entire "quantified self" movement is not correct. The issue is the time cost, not the act itself. If a trusted company came along (as if...) that sucked up this much data to allow you to answer these questions with minimal effort, I'm sure this would be a different story.

Anything at the fringes of tech with no tried and true solution requires hundreds of hours of effort. The author's conclusions are also personal, there are other styles of living and conclusions to be drawn that change the calculus on whether to do it or not.

This whole site is a rich persons humblebrag. That renders all of it moot as far as value.

I ended up doing something similar to this project a year or so ago: for nearly an entire year, I tracked every single thing I ate or drank.

Who knows how many hours I spent scanning nutritional facts on the backs of boxes, estimating amounts of liquids, and even tracking sips of water. And weighing myself! Thank goodness I used a "smart" scale at least, and I didn't have to worry about carefully inputting my weight to an app each time.

But the whole project was an exercise in perfectionism. "I have to remember this sandwich and log it the next time I'm alone" made me anxious, but once I logged it, I felt a sense of completion. The database and my personal history are now at nirvana. Everything is complete.

All for me to learn things every human alive knows today: eat more food and you'll gain weight; eat less food and you'll lose weight. Yes, I can now tell you the exact average difference in calories I'll eat, statistically speaking, on a day that I have adderall in the morning vs a day that I don't. Yes, there's a similar (but much smaller) difference in average calories per day if I have caffeine in the morning as well. And I can tell you that I generally eat an additional 200-400 calories per day on a Fri-Sun than on a Mon-Thu. Wow, groundbreaking.

I've always had a lot of water, but matching foodanddrink.csv to my HealthKit data showed that I have more water on days that I walk more steps. Mildly interesting to see it written out for me? I guess. But was it worth cataloguing every cup of water? Absolutely not.

Was any of [gestures broadly at me pulling out my phone and cataloguing each item I ate] necessary to learn that? Of course not. It gave me a chance to look back at the database and say "Wowee! I did that! Every day for a year, wow, I'm so cool!" and not much else.

It's pure armchair psychology, but this type of project always makes me think about anxiety. Who really needs this level of self observation and control? At the same time, I really enjoy reading about it and I find the window into somebody else's world intriguing.

extensive tracking of self-related metrics to improve ones health is the equivalent to reading tons of self-help books to improve ones life/social skills/...

We already mostly know what makes people happy/healthy: personal connections, physical activity, healthy diet and some sort of purpose/goal in life that goes beyond day-to-day activities. The problem is that these things generally require (hard) work and can be unpleasant sometimes, so humans do what humans do and spend unreasonable amounts of time doing the more pleasant things such as reading and gathering info rather than applying these and what they already know. (That's not to say that a project like this can't be fun or lead to insights, especially across longer time spans, but i feel like all of the questions in the first paragraph have fairly obvious answers if you know yourself at all, that don't require extensive tracking of stats to get)

Sometimes it's the journey not the destination.

I did something similar to pull data from my Garmin watch. This meant writing all manner of code to pull data out of FIT files (interesting and often infuriating self-describing file format), coming up with schemas to hold that data to make it queryable, adding visualisations, performing analysis, pattern matching, etc.

The end result is nothing really useful, I had a bunch of scripts that semi-automated some jobs that would have taken 1 minute to do manually and only ever needed to be done a max of five times a day, but I learned a load of things along the way. Often these were useful lessons that can be applied to many other things when developing software.

In a similar vein I've gone to lots of trouble to build a cooling system for my homelab rack (ESP32 to control PWM fans, Dallas 1-wire for reading temp/humidity, exposing measurements as metrics for scraping/observability, designing things to deal with the different voltages involved, etc). I could have just gone and bought an off-the-shelf solution from AC Infinity and installed it in minutes but where would the fun in that be.

I too learned this the hard way. I still haven't figured out why this is the case - like, is the inherent incidental irreducible complexity of human life too high, so it dominates majority of our actions?

I wouldnt have minded if I kept a simple daily journal with a photo a day. If I had that now with LLMs I could ask it "what year did xyz happen".

Yep. Same goes for elaborate note-taking and productivity systems. The simpler, the less bookkeeping and cognitive overhead, the better.

*quantified self

> The whole "quantified self" movement might be more about OCD and perfectionism than anything else.

Quantified Self, at least in the intended form, is focused on testing specific theories, not on collecting large amounts of data and trying to find something interesting in them.

See, for example:

https://gwern.net/zeo/zeo#what-qs-is-not-just-data-gathering

Cynical take: I didn't need to read to the bottom to know it was useless to track the correlation between drinking alcohol and dancing

If you are not sick, tracking your life like this is, like he said, is useless. Enjoy your life!

On the other hand, if you are sick like me, charting your long term heath data from doctors visits and photographing skin issues can lead to great discoveries. I have been diagnosed with Erythrocytosis and a susceptibility to mycobacteria infection which caused pulmonary nodules and skin lesions. Only after showing my data collection to my doctor. Since I have mental illness they constantly over looked my physical issues so I needed hard data to convince them of my ideas.

For those curious, I have an minor IL12B deficiency and a partial immune deficiency leading to mildly elevated levels of DexoyATP which is partially corrected with zinc supplements.

This is disappointing.... Last year i noticed large chunks of my life were being monitored via many spreadsheets and i endeavoured to bring them all together in to one Oracle DB. My plan was to eventually put some ui and graphing on top very similar to OP but seeing this is making me think twice.

The whole "this is a movement" thing might be more about mental health issues than anything else.