A.B.
I have a 2 year old who was potty trained around 20 months. I also have a 9 year old who pees the bed still. When he starts having accidents again I start waking up around 2am to get him up to use the bathroom. It's possible he's just sleeping heavier and doesn't realize he needs to go. After a few nights of me waking him up at 2am he seems to "retrain" his bladder and we go a couple weeks without having any accidents.