Question: do three year olds wear diapers?
Answer: Some kids are ready to start at as young as 18 months old, while others aren't ready until they're 3 or 4. ... Kids who are fully potty-trained by day may still need to wear diapers at night until they're 5 or so. You'll know your child is ready to be completely diaper-free when he wakes up with a dry diaper most mornings.