We converted DS's cot into the toddler bed about a month ago, so he was 17 months. We did that first to get him used to sleeping in a 'bed' and we'll be buying him a single bed (his room isn't big enough for a double) in the next couple of weeks.

He's been great sleeping in the bed, hasn't fallen out once. I've even put him to bed in his sleeping bag and he can still get out of bed if he wants to. He is a big sleep crawler too so I think a single bed would be better than the toddler bed because he'll have more room to move around. When he wakes during the night, he just cries out, hasn't tried climbing out yet. But he will get out of bed himself in the mornings and when he's woken up from his daytime nap.

For the first couple of weeks we left the sound and movement sensor pads on, so if he ever fell out the alarm would go off and we'd know but it never happened so we just have the sound on now.

We wanted to get him into a bed before the new baby comes so he is used to it and so we can then use the cot for the new baby.