They manage to do it. If you expect to commute home to the US then it's not for you. For example, I have a flight tomorrow night (Wednesday) 5 hr flight. I then leave Friday Morning back to Panama. 10 hrs block over 3 days.
That is the norm. Plus a lot of day trips. Out and back to San Jose in a 737 seems a little like overkill to me but no one ask. I prob have the easiest flight home of any gringo I know here and its still a bitch to get enough time to make it worth it.
Jumpseat request is 48 hrs in advance. No going up to the gate and jumping on.