Here's the deal: Employers will exploit your age no matter how old you are. There is no "perfect age" for a developer. When you're young, they exploit you because you are inexperienced (especially at negotiation). When you are "old" they exploit by trying to play the age card. "Not a cultural fit"--LOL--fix your stupid culture and stop exploiting people, you smug fools!

So what is there? A ten year "ripe" age range where you're good enough to code but don't have a wife and kids? Blatant exploitation of human capital.

As far as "moving up to management" that's a load of crap. There aren't enough management positions to soak up all the age 35+ developers out there. It's an extremely narrow funnel. For the winners of that race, the prize is a lifetime of quiet suffering: You'll be lucky if you retire without major depression, anxiety, heart problems, or all three. I wonder what the mortality statistics are for people who work as IT managers?

There is also this role called "architect." Do not be enticed. It is, at best, a torturous role, and at worst, it's a redundant role that people who were only so-so at coding get promoted to so they can no longer annoy the rest of the team. The effectiveness of any given architect has an exponential decay from the instant they stop coding and start attending meetings all day.

Basically, you either keep coding and stay relevant or you go do something else completely. The rest is bs. But don't for a second imagine that companies aren't exploiting you by making you uneasy about your age or whatever else can be thrown in front of you to try and confuse, diminish, and lowball you.