We transitioned our son at about 20 months. He's very tall for his age and was already more than able to climb out of his crib, so we bought a toddler bed.
To keep him in his room, we bought a safety (doggie) gate, took the door off it's hinges, and secured the gate in place. We just close it at night and can look in on him with no problems.
Now.......if we can just break him of waking up in the middle of the night and wanting to come sleep with Mommy & Daddy........ but that's a topic for another thread.
