I just got our Wreck the Halls rehearsal schedule. Next week is the only heavy one, with rehearsals Monday through Thursday. After that, it's two weeks of Monday through Wednesday, and then just a few individual run-throughs prior to tech week. This is light, and it's possible because literally everyone involved has directed/sung/played/produced/stage-managed the show multiple times. It's performed every two years and the book gets a few updates each time, but you just can't beat this kind of familiarity and flow.