My DS is nearly 3.5 and still has the odd accident. I have discouraged the potty and gone straight to the toilet. He is keener to do poos on the toilet than wees.
I must say one strategy I used was to leave him in a stinky or wet nappy for a few minutes longer than I might have before TT then go REALLY slow to change him. I would say how much quicker he'd get back to a game/TV show if he'd just gone to the loo himself.
He now sometime wets his pants if he's really busy with an outside game.
I found using his busy nature helped and making sure using the toilet was faster than a nappy change helped.
Good luck it's a tricky stage and I'm glad I won't be doing it again.