From where I sit, thinking about a 40 year old programmer in terms of "aging" is a good laugh. I started my career in the technology industry as a programmer

From where I sit, thinking about a 40 year old programmer in terms of "aging" is a good laugh. I started my career in the technology industry as a programmer at age 40 (not that I hadn't written code before that - I'd written quite a lot, but my primary gigs during that time had been in academic science, as a college administrator, and as a horticulturist). I don't think there is any intrinsic reason one should age out of software development, if writing code is what you want to do. But many people do, particularly those for whom writing code is not an end, but a means to some bigger end. Although I wrote code, and was paid for it for many years, what interested me was not the code, but the problem we were solving with it. And eventually, if that's the case, you conclude that you can accomplish more - solve bigger problems, or make a bigger personal contribution to the ones your team or organization is working on, by coding less, or not at all, and architecting, designing, and directing more. And that's the path I took. Others may wish to, and certainly should be free to, keep right on coding. But, and it's important - software development looks different from one decade to the next. Different languages, different architectures, different tools and evolving engineering paradigms. Whether you choose to remain a developer, or move into an adjacent management or design area, you will have to re-invent yourself to a significant degree, decade by decade, to remain relevant. Those that don't - well, they end up doing maintenance on aging systems with their aging skills, and not infrequently, wondering how and why their careers feel like a dead end.