I work four 8-hour shifts per week in a hospital that runs on a 12-hour schedule. There are 2-3 nurses on each shift who work only 7-3, 3-11, or 11-7; I'm one of the two 3-11 nurses on our med/surg floor. Our nurse manager can be very rigid about a lot of things, but she's really good about working with people as to schedules, and will actually create positions for folks (that's how I ended up with my current position).
Several years back when I worked at that hospital before, I was doing 12's and just could NOT handle it physically; she had me get a note from my doctor explaining that I could not work 12's because of my foot and joint problems, and promptly 'found' a spot for me on the 11-7 shift. (It was later on that I learned that nights were NOT for me, as I became forgetful and confused as to dates and times, and thought I was losing my mind.....turned out all I needed was a change of working hours.)
Then, when I came back last winter, she offered me a part-time, 8-hour position that she'd created for me, and that's what I've been working until recently when she offered me the full-time spot. Almost everyone else continues in the 12-hour routine, but I stay with my 8's because I know I can give my best.......when I worked 12's, I was often half-past give-a-sh** by 4 or 5 AM, and that, as we all know, is NOT the attitude to have when you hold patients' lives in your hands!! Not to mention the fact that EVERYTHING hits the fan at 0600.....the call lights start in, everybody has to go to the bathroom, and the one patient you've been worrying about all night will a) fall, b) go nuts, c) have a giant Code Brown, d) bottom out their blood sugar, e) have a seizure, or f) code. And that's not the time to be so tired that you can barely heave your sorry carcass out of the chair and move with all the speed of a weary blacksmith!