No more than a few hours, for trips I've actually taken. Rare for it to be that much; usually 1-2 at most. I think I've maybe de-planed once?

I had what would have been a 12+ hour delay earlier this year with a flight pushed to the next day. But at that point the trip wouldn't have been worth it, and I just drove home and cancelled it. Felt bad for the 777-worth of pax forming a line for AA customer service at CLT, at like midnight 😬