When they were up to 8 & 9 yes they were always sharing a room.(Two boys)...it made them very close.Then once they had their own rooms...no.
But 4 years later, they were back in the same room again, as we moved house.
I feel if both the same sex.....they can, it was a very positive idea we had.
Of course up to 4-5 they still could share, if the same sex......but after that not really fair for them.
Boys like their rooms with boy stuff, and girls ..well we know what they are like :)
My two youngest girls shared a bedroom up until about 13. Early on it was fine but the older of the two was a neat freak and the younger, the untidy one. Often the older one would clean and tidy up the bedroom only to have her sister mess it up again so that caused a few problems until we prepared the other bedroom and one moved over into it.
My nieces used to share a bedroom, however now they no longer need to as the upstairs bedroom was cleared out to make room for her. They're ages 8 and 9 respectively. The 8 year old still uses the bunk bed. They live in a 5-bedroom house, so therefore they don't need to share a room now. Sometimes houses with two bedrooms and two kids must share, they have no other choice.
No, we're lucky enough to have a big enough house that they don't need to. Which is good because my oldest two are a boy and a girl. The baby still sleeps in my room, but when he gets older he'll share with his brother.
Our 2 daughters had their own bedroom, in our 4 bedroom house. The eldest daughter has 2 young daughters who share a bedroom, as our son-in-law has to have the spare bedroom for his film work. (They live in a 150 something year old house)
Our 2 daughters had their own rooms in our 4 bedroom house. The eldest daughter now has 2 young daughters, & they do have to share, because their father has to use the 3rd bedroom for his film work, as they only have 3 bedrooms, in their 153 year old house.