My 4 1/2 year old son was day-time potty-trained by the time he began preschool (a little before he turned 4 years old. A few months after he started preschool, we noticed that his pull-ups were dry every morning, so we switched him to underwear at night time too. Finally!!! One child down and one to go! My daughter just turned 3 years old yesterday. She is mostly day-time potty-trained. She wears her big girl underwear every day and only has an accident every couple of days. Usually, she has the most accidents before bed. I think it is because she is tired and she just doesn't feel like getting up to go to the potty. She will be starting preschool in the 3 year old class in the fall and she will need to by potty-trained by then. At least day-time potty-trained. I think that getting her into preschool this year really helped since she sees most of the other kids doing it and she wants to be a big girl too. One thing that really helped us on our potty-training journey was to have our children pick out their big kid undies The were so excited to pick them out and the really wanted to keep them dry so they don't ruin them. We have the summer to get our daughter potty-trained. I think we should be OK.