I would define "old" as the age when one can no longer adapt. There are common trends like people older than Gen X struggling to learn how to use a smartphone.

I would define "old" as the age when one can no longer adapt. There are common trends like people older than Gen X struggling to learn how to use a smartphone. Or attachment to antiquated notions around gender roles, for example. But if I'm being honest, I stopped adapting sometime in the mid-2000s, also when smartphones arrived and Moore's law for CPUs ended with attention shifting to GPUs. I just haven't had passion for most tech since, because most of it looks derivative to me or even like a step backwards. I simply can't work the way that I'd like to with current technology. And the barriers to entry around stuff like semiconductor manufacturing are so high that I can't use my degree there. So in a very real sense, I can't do anything but wait for the stuff I daydreamed about back in the 90s, that I thought would be here by now. Like how Paul Graham said we compress 40 years of work into 4 year working at startups: http://www.paulgraham.com/start.html http://www.paulgraham.com/start.html My final test may be the most restrictive. Do you actually want to start a startup? What it amounts to, economically, is compressing your working life into the smallest possible space. Instead of working at an ordinary rate for 40 years, you work like hell for four. And maybe end up with nothing-- though in that case it probably won't take four years. I've been trying to win the internet lottery for almost 25 years without success, so mentally I'm somewhere around 250 years old. At this age the mental fatigue is almost all-consuming. I'm just so tired. Working this hard for so long without an equivalent amount of rest or a win has kept me in near-continuous burnout for more than half my life now. Subjective time at 45 years old passes about 3 times faster than wall time (assuming 1:1 at 15). So I'm finally punctual, not by adding a time buffer, but by dividing the time before an appointment by 3. If I have an hour to be somewhere, I really only have 20 minutes. I'm expecting that time compression to keep increasing at that rate as long as fundamental injustices in the world aren't addressed. Loosely that means that if we don't have UBI, true labor-saving AI, equal access to capital, etc etc etc so that we can pursue our life goals and feed our inner child, then I'll be compressed 9:1 by 65 and 27:1 by 85 (if the loss of social security finally eliminates retirement). At which point my mental clock won't be able to run fast enough to keep up with the churn of the modern world. The struggle will eventually come to dominate every facet of my life, while wealth inequality will have others sitting on lifetimes of money they could never spend. Somewhat ironically, I don't care how much money they have or what they do with it, only that I'm still under the yoke of forced labor as rents are artificially inflated well past the point of believability.