I can't really remember with my first two, though I know my daughter was fully night and day trained before she was 2 1/2. I have just gone through toilet training DS2 who is 2 2/3, and he's night trained himself too. I still put a nappy on him because he sometimes doesn't make the toilet his first pit stop of the morning and wets it first thing, but if I manage to catch him and send him to the loo on time, he is dry from the night before.