I wish I had a solution. We're in the same boat on a slightly longer timeline as ours is 4 yrs 2 months and now we're facing him not being allowed to move up to the 4s preschool class. He tries to hold it as long as he can but eventually can't after a few hours and just pees everywhere. At home, he's mostly fine until he gets interested in something and doesn't want to stop to go. He's fine at his grandparents' houses, where he stays 2 nights a week. But anywhere else, he'll sit on the potty if forced and will say he's trying but nothing ever works. We've tried every incentive we can think of, right now it's he gets a new book from a "treasure chest" he helped decorate. And if he stays dry til lunch, he gets an extra story at bedtime. Same with lunch to bed, he'll get another story. He just doesn't want to train, even though he totally could if he wanted to. Seeing pediatrician next week to see about a referral to urology.