If I may ask, what changes when you're older? Is it mostly the mental stamina? Or is it the body asking you to spend time resting? A combination?
Plus the whole idea that money earned is a function of hours worked itself is wrong. It sure is some times, but most of the times it isn't.
You also burnout, age quickly, catch diseases like hypertension and diabetes when you go through repeated stress and over work. You miss out on exercise and good diet. Most of it has impact on your well being.
On the other hand money making seems to depend on a myriad factors like luck, office politics and not just working hours alone. So optimising for one parameter just doesn't make sense logically either.
When I realized striving for that perfection had zero positives beyond my own perception and tons of negatives, it was easy to find a better work/life balance.
Working for glory never really makes sense in any field of work. This mostly due to Ozymandias factor. But for most people the Ozymandias age is a pretty small number. I don't even remember names of several colleagues I've worked with early life, so to expect any kind of recognition or even that some one cares about your work is just plain delusion.
Most people struggle to remember what they had to dinner two days back. I'd like to imagine managers don't remember whose getting the word done, as long as it is getting done.
Beyond all this most products/projects/service(s) have a short life, and are EOL not very far from their creation. So it just doesn't make sense to do permanent damage to your life for short lived easily forgotten stuff.
When I was young, if some management type had told me we were going to miss a deadline I would've pulled all nighters, worked weekends, whatever it took to help bring the deliverable in in time. Nowadays (at least before I stopped working) I would just say something like "Okay, let me know when we have an updated schedule." Before, when my manager had said we need to work weekends, I'd be there. Now, I'd just say that I'm not doing that.
The confidence comes from experience, knowing that I could get a different job, being financially secure, and a self confidence that I didn't possess in my youth.
Hopefully there will be time to come back to younger sprints when they’re older, but if not, being a parent is making peace with that. Can’t have it all.
How many death marches can you look back on N years later and think "that paid off, I'm happier now because of it."
Once you have been coding for 10+, 20+ years you'll come to realise that there is a repeating set of problems you're solving. I haven't seen a truely new problem in a long time. Granted the predominate code I write is for corporate web apps.
But starting out in my 20s everything was new and fun. The reward for solving a thing, or shipping a feature felt great. Now its just one of many features I have shipped that are all more or less the same.
Also another big factor I think is I am significantly more productive now than when I was in my 20s. I would have had to work 80+ hours back then to keep up with myself now
Here is a sermon that I like. It might seem contradictory at times, as it uses terminology specific to Buddhist and Taoist philosophy:
I think many people in their 20s don't understand what a mental edge they have over ancient people like me (32) if they really test the limit of their mental strength.