My DS (2.9) can easily go 6 hours between wees...even 8. He drinks a lot, he just has a huge bladder/impressive bladder control! He'll have a wee at bathtime (6.30pm) and then not need to go again until half nine in the morning, despite having a big drink of milk before bed and some with his breakfast!
He was dry fairly quickly, with a couple of regressions. I actually found that being understanding about accidents (once I knew he was capable of staying dry) didn't really help as they sent the message that it was ok to wee in your trousers after all. Being firm 'we do NOT wee in our pants, that is NOT ok' worked much better for us. I know that this goes against most advice though!