When I got married almost two years ago (wow, time flies!), both my photographers and my videographers offered to come to our rehearsal which took place two days before the wedding. I thought that was an excellent idea. They can get a heads up on the different players for the wedding, meeting your key family, relatives and friends in advance so they know who to go to should issues arise during the day of the wedding. There will also be less surprises during the ceremony and they will be better prepared knowing where they should stand and shoot from to get the best shots. Some photographers and videographers are more than willing to attend you rehearsal, others aren't, but it doesn't hurt to ask!