A.H.
I've always been of the mind "move them when the start climbing out of the crib". Whenever that time comes I have found the Nanny 911 advice the most helpful as far as getting them to stay in their bed. At first you put them in their bed and go through a bedtime ritual (whatever that is for you...reading, singing, talking, etc). Then when they keep coming out of their room for one more drink of water, just to tell you something, just to get something, etc. You tell them that it is time to follow the sleep rules and you put them back in bed. Each time they get up after that, you put them back in bed with NO CONVERSATION, NO INTERACTION, NO EYE-CONTACT. The child is looking for interaction with you so you don't interact with them and that way they will learn that this is not the time for interaction with mommy and daddy, it is time for bed. The sleep rules are (1) Stay in bed (2) Lay quietly (3) Lay still (4) Close eyes (5) go to sleep. Those are even good rules for the older kids when they "forget" how to go to sleep...