Bedroom share - are there any unwritten rules?

[cba]

Ok, just found out we are pregnant with number 4, huge shock. When we told mil, the first thing she said was, well where is everyone going to sleep. I had not thought about it. Baby will be in with us for 6 months at first.

So we have four bedrooms, with ds1 who will be 9 ds2 7 and dd 4. So would you put the two boys together, dd leave, baby own room.

Or does ds1 have his own room being the eldest, and either ds2 or dd share once baby old enough.

Only thing with that is there will be a bit of an age difference and both ds2 and dd are quite particular with their things.

And just to throw an extra spanner in the works we could convert downstairs playroom into a bedroom??

What does everyone else do?

congratulations!
I shared with my brother (who's 3 years younger) until I was 8, I don't remember it being a problem but then I didn't know any different. If you can afford it I think that new bed or decorating the room would certainly make it more appealing