I sleep through the night 90% of the time with no problems. And most of the time, I don't even need to empty until sometime after breakfast. I was probably nervous when I first got my pouch about recognizing the need to empty while I was asleep, but it has honestly never been an issue. If the pouch needs to be emptied the pouch wakes me up! Like when you gotta pee... and I always wake up before the 'overfull' and painful stage.
Honestly, I had more trouble sleeping when I had an ostomy bag because that thing can fill up and you'd never know it! I kept thinking what if I roll over on it and it bursts??