DS announced at 2.5 that he wanted pants instead of nappies. Day 1 he had an accident and immediately wanted a nappy back on which I did. Day 2 - 8 he was dry Day 9 - now (around 4 weeks) it's hit and miss. Some days he tells us every time he needs a wee, other days he won't say a word and will just do it in his pants. I send 5x pants and trousers to nursery - some days I get them all home dry, others all home wet, some days in between Poos are nowhere near consistent but I'm not too worried about that as I've been told frequently that poos can take longer to get right
There isn't anything that consistently motivates him - some days he'll do anything for a sticker, other days couldn't give a monkeys. Same with pennies, small sweets etc.
So, keep going and hope the 'lots of accidents' days get fewer or......??????