We honestly bought 1 pack of pull-ups for our son and realized they were glorified diapers. So, we stopped using them.
During the day, it was underwear. At night it was diapers. We occasionally still put a diaper on him despite being potty trained over a year. He's had less than 10 accidents, and we can't predict when they're going to happen. Of course, when we do put one of his sister's diapers on him, he's dry as a bone.
However, it can take kids a long time to master overnight dryness. We have friends whose daughters still wear pull-ups at 7 years-old. A lot depends on how hard they sleep and their ability to recognize a full bladder while sleeping.
Good luck! That's what happened with us - completely lucky with 1 kid - don't think it will strike again with the 2nd.