As I've moved into more analysis/inside technical work, I've occasionally had to work long hours inside. Whenever I need to do this, I'm reminded of how much more draining office work is. Sure, in the field I'll work 10-11 hour days with no ill effects, but a lot of that time is running around, collecting measurements, taking notes, and watching contractors.
I fit the extra office-type work in the office. I'm not the sort of person who can work well at home - I prefer to have a clean break from whatever is stressing me out. Even in grad school, where my setup for my apartment and my office at school was essentially the same, I would still make the trek in to do my homework. That means that in a pinch, I'll haul myself all the way to the office on a weekend to work. And because I'm a morning person, and if I'm stressed/under deadline, I will tend to go to bed early in an attempt to get more sleep and then wake up extremely early, I do all my extra office work before hours. By the time close of business rolls around, I may have already put in 10 hours and am wiped out.
I have coworkers who prefer to work extremely late, and ones who prefer to hide out at home to avoid distractions. I also used to work with someone who would take his stuff to a local bar to catch up on work. Of course, the best alternative would be to have a reasonable schedule and not have to work a ton of hours to catch up, but with project-based work, we rarely have the luxury of spreading out the workload.