My daughter , now 2 and a half uses her pull ups as "sleep knickers". She has progressed to now wearing underwear during the day and no actual "Nappy" for sleep time. I found it more rewarding for us both to advise she now has "special Pull Up knickers" for her sleep times as she feels she is not a baby anymore but advises us she is a little girl and she NEEDS to wear knickers to bed (knowing that she may have little accidents at sleep time she feels much more happy now wearing the pull ups at this time and is willing to go to the toilet before her sleeps and checks whether she did or didn't wee after her sleeps and gets very excited when there is minimal in her Pull Ups as she is working at being a little more wee free). We didn't use pull ups as an advancement from Nappies for toilet training during the day as she worked out after the first time she used them (we called them special going out knickers) that she could treat them like a nappy and there was no incentive for her to go to the toilet as she knew she could be lazy rather than have a true accident.