I have three children: DS (11), DS (6) and DD (6). We live in a three bed flat and 11 year old has a room to himself and the twins share. We will be shortly moving to a four-bed but I want one room as a study as I work from home and it is impossible to work in the lounge with everyone at home.
DH and I disagree. I think that the two boys should share (which the eldest doesn't want to do but he could always do his homework in the study if 6 year old is being a pain) and DD should have a room on her own. DH thinks the twins can share for at least until they start secondary school by which time my older son won't find his little brother so annoying (maybe).