I used to have dd1 and dd2 share a room it started when dd1 was 3ish they shared for about 5 years it worked well, occasionally they would have there bad nights but being 22months apart I think helped, they liked the same things went to sleep around the same time and loved being around each other :-)
currently the 3 older ones ( dss, dd1 and dd2) have their own rooms
Once dd3 is 3 (another year) she will be moved out of my room into dd2 room (it's the old master bedroom so plenty of space ) there is 5 years between them.
once ds1 needs his own room (he is only 5months) dss should have moved out he is 17, if not we would need to look at getting a bigger house.
I don't want dd1 and dd2 to share again dd1 needs her own space she would have suited being an only child 😁