A little of each. Some offer Saturdays which is very nice of them. Others you just had to juggle. All of my professors were hookers and stated in their syllabi that they didn't care about professional school interviews...so they made zero concessions. So you just do what you need to do. A few gave me a few dates to pick from. Others just asked if I can be there on this date. I suggest not trying to haggle over dates or coming off as too needy and changing dates around after scheduling. They'll gladly toss you aside if they sense any of that nonsense. If they give you a two week notice, make it happen. I skipped my brother's wedding for one of them. That's a little extreme, but I didn't come all this way to mess around.