How Do you fit working out when you work 12-hour days ?

Just curious if anyone out there works 12 hour days and how they work out? Do you just skip those days and work out on other days? I've been working a lot of 10-12-hour days and when I get home, I'm absolutely exhausted. I get up very early, and when I get home I just want to eat supper and rest. I don't have a very physical job, mainly desk, but have been putting in a lot of hours and just want to sit and not even think when I get home!! LOL. Just curious if anyone pushes through and tries to get in a workout if you have work hours like this. Thanks!