You _can_ avoid this. It seems (based on my experience, at least), a duration-of-tenure problem, not an age problem. Switching fields when you're heading toward

You _can_ avoid this. It seems (based on my experience, at least), a duration-of-tenure problem, not an age problem. Switching fields when you're heading towards "landmark" status does seem to do the trick. It's scary as heck, but you can avoid that corner for a while longer.