I think it depends on your LO. Ella moved into a big bed at around that time - always been an angel sleeper, never got out or had any problems at all. Jack was 2 in March and is still in his cot!!! He's very spirited and someitmes takes a long time to go to sleep - whilst he is quite happy in his cot if he was in a bed he'd be up and down like a yo yo!! I keep joking with dh that i'll move him to a bed once he's fallen out of the cot 3 times (JOKE - and no, he's never fallen out!) I'm not moving him any time soon!!