My two girls (4 and 2) have been asking to share a room for months. We are expecting LO3 in a few months, so we thought we'd give it a try while there was still time to adjust. (We have four bedrooms, but if this worked out we'd keep the guest room as is for now and update/reuse the nursery.) We moved them in together this weekend, and it has been a total sleep disaster since. They're bouncing around and playing in the dark until 10:30pm (bed time is 8) and nap/quiet times are definitely not that. I'm thinking we'll give them two weeks and then reassess, but I wondered what others' experience had been. When your kids began to share a room, how long did it take for the novelty to wear off and for them to settle into a new routine?