Let's talk about when you should stop using diapers during toilet training. Typically I recommend stop using diapers as soon as you start toilet training. What that means is your child should be wearing underwear full time when you're doing potty training. If you're concerned about an accident, have your child wear underwear in the car or at bedtime but put a diaper or pull up over the underwear so that he doesn't soak the seat or he soaks the bed. But it's really important that once you start potty training that your child never feels a diaper against his skin, that he only wears underwear full time. You will go through lots of underwear during potty training but that's okay and your child will have accidents during potty training and that's okay as well. But if you're switching back and forth between a diaper and underwear then your child could get confused so it's really best that once you start training that your child wears underwear full time.