I have two daughter, 6 1/2, and 1 1/2. They are sharing a room due to space restrictions in our house. Sometimes I feel it goes well, sometimes, not so much. IMO, I would much rather have them in separate rooms. My LO is still in a crib, and my older daughter has a loft bed. My LO is always climbing on the loft bed when she's in there playing, which makes me really nervous to transition her to a toddler bed. It is frustrating when one wakes up in the middle of the night, the other one almost always wakes up too. My older daughter get's really frustrated when she just wants to play in her room but it's nap time for the LO. In my experience it hasn't worked out great for us, but there are lots of factors to consider when having kids share a room, and ultimitely you won't know if it'll work for your kids unless you try it out (and give yourself a good month or so to work out all the kinks). I have a friend who has 3 (1,2,3 y/o) and they all share a room, just one queen size mattress on the floor. It seems to work great for her kids, but that's all they've ever known.