We made the transition when our son was suddenly able to climb out of his crib on his own. It really depends on the child, as to when the change should be made. In your case, I would start by moving his crib into his room, and letting him get used to the idea of sleeping in the room, before having the new bed to deal with too. Then, when you think he is used to it, give it a try in the toddler bed. You might want to consider placing a baby gate at the doorway to his room, at first, after the switch to the toddler bed. This will give you the added peace of mind of knowing that he isn't going to get up and wander through the house while you're asleep, keeping him safer from whatever of the many things that a young one can find to get into when we can't be over their shoulder.