How long can you reasonably keep your lo in your bedroom?

Eli was in our room til he was 8 or 9 months, by which time I'm afraid I was rather desperate to get him out. However at the time we only had 2 bedrooms to play with, so he moved into Megan's bedroom. I wasn't too sure whether it would work out, but it really did - they got used to each other pretty quickly and loved sharing a bedroom.

Is there any reason the new baby couldn't share with E?  Abigail was in with us for 6 months, Lily for about 8 months I think, then we moved her back in after a month cos her sleep was all over the place and as she was sharing with Abigail it was easier, she was then in with us until we moved when she was 14 months.

Charlotte is almost 2 and still in with us. We only have 2 bedrooms and there's not enough room for her cot in Lydia's room so we'll have to wait until she's old enough to go in a bunk.

Thanks for your replies.

E's nursery is very small, just enough room for his furniture, definately not enough room for another cot.

We do have a double spare room, but can't use this as have to keep it available for mum, its sort of become 'Grandma's room' !

If we do make our bedroom bigger, it should be quite a bit bigger so will have plenty of space for a cot. We will have to extend again though to put kids rooms upstairs. What a faff. We don't want to move though. We could move to the farmhouse, but its a working farmhouse and I don't like the idea of everyone in and out when I have a newborn baby to look after, I remember spending most of the first few weeks with my boobs out trying to get E to feed!

Zac is 23 mths and co-sleeping.