T.H.
I moved my first at 15.5 months and my second at 16.5 months- my first fell out of the crib once so that helped, we started with the box spring & the mattress on the floor in his 'new' room so he could play on it and still nap/sleep in the crib for a couple weeks, then we moved to naps on the bed for a week then just put him in one night and he stayed! We have a gate at the top of the stairs but for the first couple weeks we put a gate up at the door of his room to keep him in, a few nights he would stand there and look for us or play (we keep 'quiet' toys in his room) then crawl back in bed when he was tired! We haven't had any issues with either of the boys and they have been sharing a room now for 2 months- they love it!