The most time I've stayed in the same wet diaper was for 2 days before and after that time I started getting a rash and the pee started turning to ammonia and my penis begin burning a bit due to the pee turning into ammonia.
So I would not recommend staying in the same wet diaper for 2 days even though it can be fun for a bit until you get the rash.
Now I change after 3 to 4 hours in the same wet diaper to avoid a rash because I wear diapers full time now and no longer use the toilet for either pee or poop.
Diapers are now my toilet so I change more often now.
The most I would recommend staying in the same wet diaper is 24 hours before changing if you have a high capacity diaper to wet in that absorbs a lot of pee.
I've once stayed in the same wet diaper for 2 days before when I had a few days off from work and was wearing a very highly absorbent disposable diaper.
The diaper was ABU Super Dry Kids diaper and held up really good for the first day before it started leaking but I still wore the diaper and would sit on the toilet when I needed to pee and pee in the diaper and let the pee leak out of the diaper and into the toilet to avoid a mess.
The wet diaper felt very good and I masturbated in it a lot as well.
But after 2 days I changed out of the wet diaper before going to bed that night because I was starting to get a rash and the pee was starting to turn to ammonia.
So I would really recommend not going any longer than 10 to 24 hours before changing a wet diaper.
I now wear diapers all the time and use them for both pee and poop and I will change now after 3 to 4 hours when the diaper gets wet enough to change.
I can now afford to buy diapers for 24/7 wearing and have enough diapers to change into so I change more often now.