I'm 30 going on 31, and am currently doing that. I recently came from a start-up gig that worked me until I burned out, then laid off my whole team shortly after launch. I'm at a medium sized company that still does cool things, but doesn't force ridiculous deadlines on you and actually seems to care about the well-being of their employees. Most of the engineers have been there for 2-10 years; I've heard this should be a metric by which you determine your next position, but I hadn't realized just _how_ important that is until I got chewed up and spit out by a 'cool' startup.