My girls are 3.5 and almost 2, and they sometimes wind down together in my older LO's bed. My younger LO has gotten cozy and layed down and my older LO asked if she could sleep in her room. We said no because LO's bed is high off the ground and I'm not sure they would actually listen and go to sleep. I think in the next year or so we will let them sleep together, occasionally, if they ask!