I moved my first at 20 months, when I was 4 months pregnant, so that the first would be used to his new room and bed long before baby came. With the second, he moved into a bed around the same time as he crawled out of the crib and fell on the floor in the middle of the night. Both times I moved them inot a twin matress on the floor, then up on the frame once tall enough that they could climb onot the bed. I skipped the toddler bed altogether as I thought it ia a waste of money for something you use for such a short amount of time. with the second we bought bunkbeds, which right now are being used separetly as 2 twins until the oldest is old enough to be on the top bunk.