Toward the end of my drinking I started to have mini blackouts. By that time I was mostly drinking at home, and as a quiet drunk nothing serious ever happened. I normally go to bed by 10pm, and the way I experienced it is that I would wake up in the morning and remember it being something like 8:30pm, but I had no recollection of the time after that or going to bed. I'm assuming I went to bed around normal time, so I'd lose an hour or hour and a half.