P.K.
My grandson was 3 1/2. Would not use the potty. Then one day I told him I wanted to sign him up for a gym class. He as excited. I knew he could not go because he still wore diapers. We went to look at it. I gave the girls the heads up. They said they were excited to have him join. Then they said oh you do not wear diapers right. You use the potty. He had to admit that he did not use the potty. We went home, took his diaper off and used the potty. After three days I signed him up. No accidents ever. He was being stubborn and lazy. So that is what worked for us.