17, ~25, ~30, ~40, ~45, ~65 and even ~70. I think it depends on the personality property of curiosity to delve into the software-hardware stack turtles of details all the way down and not see anything as a real barrier that can't be overcome with effort.

There's something to be said for lots of experience shipping product under a deadline, politely questioning technically-expensive features that wouldn't be good for the user and managing stakeholders' expectations.