Well we've had a lot of bedroom swapping over the years lol.
Lydia slept with us until she was 22 months and then went into a room on her own.
At that point Alex was born, so he stayed with us until he was about 18 months, and then he went in a room on his own, so both Lydia and Alex were in separate rooms.
When Alex was nearly 2 (and Lydia nearly 4) they both decided they wanted to share a room, so they went in with each other.
Jason was born the day before Lydia's 4th birthday (Alex was 25 months old) so he stayed in our room.
We moved house when Jason was 10 months old. It was 1 month before Alex's 3rd birthday and 2 months before Lydia's 5th birthday.
In the new house, Lydia and Alex each got a room to themselves, and Jason was with us.
When Lydia was 5 and a half we got bunk beds. She and Alex started sharing a room again together with the bunks, and Jason (who was 1 and a half) went in a room on his own.
When Alex got to about 5 and a quarter (Lydia was roughly 7 and a quarter, and Jason was about 3 and a quarter) we had another switch around. Lydia went in a room on her own, and Jason started sharing the bunks with Alex.
So at the moment Lydia is 9 and is in the small room on her own.
Alex is 7 and is in the top bunk with Jason who is 5 at the bottom bunk, and they're in the 2nd bedroom.
Nathan is 17 months and is still in with DH and I.
In the new year at some point DH and I are going to swap rooms with the boys, and Nathan will be in with his brothers then, given that the master room is the biggest so the three of them will need the space.
If we had more bedrooms I would DEFINITELY prefer them all to be separated because Jason is the biggest chatterbox EVER and he always keeps Alex awake, but we only have a 3 bedroomed house so there's not much we can do. Luckily the master bedroom is really big.