Depending on the director, more and more I find myself coming up with a scheduling and handing it to the director for them to look over. (One director I work with I tell him what time to show up the next day, and what scenes he is rehearsing, and that's about that.) I will tell my director, often, that costume fittings have been requested for a certain day, and that I am having trouble getting them all scheduled . . . can I pull someone from a scene they just stand around in, or something like that. But, the schedule is usually what I am working on during the day.
My current director works on a schedule a week in advance, but changes it daily. I have to tweak it a bit to get costume fittings in. (right now, I have about 65 hours of costume/wig fittings requests to get in by Friday . . . and still get some work done.)