How did you do it, how long did it take, what worked and didn’t work?
We did it the same time we started day potting training. We cut diapers cold turkey when my son was 3. We put about 2-3 layers of waterproof mattress pad and bed sheets so if he had an accident at night we could easily peel off a layer and have fresh sheets underneath. Then I’d wake him at 1130 and 2am to pee. We kept the potty by his bed so literally I got him out of bed, took off his pants and set him on the potty (we kept lights off so he wouldn’t fully wake). The whole thing took just a minute to do. He got consistent with no night accidents in about a week. So then I just woke him once at 2am for another week or so. We also go commando bc undies feel too much like diapers. He was completely night trained in about 2 weeks. We also limited his water intake leading up to bedtime.
My son pulled off his night diapers about 3 months after we started potty training, so we put the toddler potty with a boot tray under it in his room and when he would stir in the middle of the night, I would get him from bed in the dark and sit him on the potty. After about 3 months he started getting up on his own. He never really had any nighttime accident unless I slept through him waking up at night.