At 40? If you're suffering from loss of mental capabilities to the point that it affects your performance at work at 40, you have medical issues that need immediate attention.
> simple economic math ( fresh meat is cheaper and more malleable )
I've seen this stated many times, but nothing is forcing anyone to offer a particular salary or demand a particular salary.
Not sure that I agree on the first point. In my 20s, I could easily work 12 hour days, keep tons of complex state in my head, and almost never walked into a room and wondered why I went there (both literally and in the programming metaphorical equivalent).
In my 40s, much of that has changed. I'm beat mentally after a 6-7 hour day of coding. I can only keep smaller portions of the system in my head easily.
It's possible that I was blissfully aware of how shallowly I understood things or how ineffective I was in hours 7-12 of a workday in my 20s (and both of those no doubt have shreds of truth in them), but it seems way more likely that I am noticing a genuine difference in mental ability over the intervening two decades. None of that seems medically abnormal to me.
I'm mid 30s, and if anything I can keep more of the code in my head than when i was in my 20s. My abstractions got better, and I've seen lots of stuff before, I think this has had the effect of compressing everything.
I think of all the edge cases and pitfalls that I wouldn't have in my 20s. I have an easier time reading and understanding documentation, using libraries, reading and understanding other people's code. I think I'm also much more sympathetic to the poor sod who wrote this broken code under a time crunch 5 years ago.
I think you're selling yourself short. In your 20s, you have a lot less mental baggage to deal with, on so many levels. This is a good thing when you need to work hard (which we all did when we were young :) ).
Even if you can only work 6-7 hours a day now, you're most definitely spending that time a lot more efficiently than you did a decade ago. You don't need to keep more information in your head at the moment because you have decades of wisdom guiding your decisions.
It's hard to deny that one's memory deteriorates before age 40. But does it really matter that much to job performance? I'm not sure, but then I'm not a professional software developer, so that might explain our differing views.
I do have to disagree about the number of hours worked being a sign of mental degradation. I'd call that physical degradation, and to be honest, I'm able to work longer days now than when I was 30. Everyone's mileage will vary on that, though.
For me, what dominates everything else wrt mental performance is that I'm much more efficient at learning things now than I was in grad school 20 years ago. Whether it's a new technology, a mathematical proof, or reading someone else's source code, I'm massively more productive than I was at 25. If anything causes me problems, it's that I enjoy learning new things too much, and I spend less time than I should doing the work that pays the bills.
Executive and working memory decline is a real thing that happens with age, I didn't say I'm demented to a point where I suck at my job, but I definitely felt a slight decrease from my 20's to my 30's.
> I've seen this stated many times, but nothing is forcing anyone to offer a particular salary or demand a particular salary.
I didn't think bosses& hiring managers trying to pay the minimum and get the maximum was a contentious point. Our industry is still made of young people who prefer younger people to do their work, for both economic ( many times short sighted ) and social reasons.
> brain "degradation"
At 40? If you're suffering from loss of mental capabilities to the point that it affects your performance at work at 40, you have medical issues that need immediate attention.
> simple economic math ( fresh meat is cheaper and more malleable )
I've seen this stated many times, but nothing is forcing anyone to offer a particular salary or demand a particular salary.