I created htmx (intercooler 2) when I was 40 and it has been far more successful. I also created hyperscript when I was 40.
I'm working on new stuff as we speak.
I could have made a lot more money by moving over to tech management at around age 30, which is what I think sucks a lot of programmers out of the game, but I like writing code.
I do have memory issues compared with when I was younger, but I've been coding so long that the total set of stuff I know about is huge comparatively. I'm also much less intimidated by technical challenges since I have a lot more techniques I've successfully worked with and I'm more patient with problems.
I'm definitely not the same programmer as I was in my 20s, I can't do weeks of 12 hour days in front of the computer like I could then, but now I have a much better and more intuitive understanding of what needs to be done, so I waste a lot less time.
I tried to summarize what I've learned here:
But, to answer the original question... wait, what was the original question?