There is the danger of over preparation, of loss of spontaneity; over rehearsal is the most terrible thing you can imagine. We do have a very close association between costume and set designer, though. And the cameraman is very important, of course.
You've got to know your limitations. I don't know what your limitations are. I found out what mine were when I was twelve. I found out that there weren't too many limitations, if I did it my way.