That probably depends a lot on the person, but judging from previous threads almost no one has started involuntarily wetting overnight (wetting their diaper without waking up) regardless of how long they've worn. There have been a couple exceptions, but it's very rare. I know I personally have gotten up and been changing for morning, thinking I hadn't used my diaper at all that evening, and been surprised by a diaper that was a bit wet. But in every case, when I thought about it, then I did recall "oh yeah, I did wake up once and wet a little before going back to sleep". It can be difficult to rememeber what goes on during short wakeups at night. So if you <i>do</i> happen to wake up wet, and don't recall going, maybe you did and just don't rememeber it. I think that may explain a chunk of those that think they've slipped slightly into IC from diaper wearing overnight.