J.C.
I put both of my kids in a twin bed at 15 months. I have a friend who has her almost 2 1/2 year old in a crib too, and I wish she'd move him out of it. It's so much easier to transition children before they're old enough to grow attached to certain things. Both of my kids slept through the very first night of sleeping in their twin beds, without a flinch, even when I first laid them down! I just put up a safety rail and lined the foot of the bed with big floor pillows. I broke my kids of things at younger ages, so therefore never had to experience any of the things women talk about, like "how do I take my kids' pacifier away?" I took pacifiers away at 6 months, so my kids could learn to soothe themselves with their minds, and not a material thing. I took bottles away at 12 months, and my kids never even cried for them. Bed at 15 months, I think I'm onto something here since my kids have never had to suffer being broke of a particular act or object.