I would say I spend about 8-10 hours overnight in a wet diaper. During the day it varies between 2 to 4 depending how wet I am and the activities i need to do.
I've hit about 24 hours before as well. I have to point out, though, that by that point just about any diaper is ready to give up. I definitely could have gone longer but to be honest I didn't really want to, and I usually enjoy getting a lot of mileage out of one diaper.
The longest I have been in a diaper has been about 24 hours and that was when just about every inch of the padding was used from multiple wettings and I loved being in a soaked diaper.
I usually get into a new diaper after dinner once I've showered. Then I got to sleep, wake up wet in the morning and normally I have breakfast first then I change (if it's a weekend).
Several hours and until the poor thing is busting at the seems. I don't wear to bed and couldn't wet at night if I wanted to, my bladder is the very string side, to the point where I woke it and near painful from holding so much.
The longest time in the same diaper was about 12 to 14 hours, all but 2 or 3 of those hours, the diaper was wet. I hadn't intended to stay in the diaper that long but I just didn't feel like changing.
I am very prone to rash, unfortunately. So, I can stay in a wet diaper maybe up to 30 minutes, 1 hour tops (if absolutely necessary and can't change soon enough).
I usually try, if possible, to reach near full capacity so it can vary from just a couple of hours to almost 24 hours. I think the longest as been around 18 hours. Just last weekend i woke and my diaper wasn't very wet so i stayed in it until mid-afternoon.
I always wear my nappies to the point of leaking when at home. If I'm going out I will put a clean dry one on so I don't leak in public. I often stay in the same nappy all day.
14 - 24 hours so so though the tapes on the diapers almost always end up messing up before the diaper has reached full capacity.(max of over 24 hours with very absorbent diaper)
Wear almost full time at night so "dressed" for being wet for 12 hours, that is using one large booster and plastic pants. Never a rash. Daytime for traveling, so max 4 hours wet.