We used about 5 a day during our November trip, and were probably late for about 2 a day or so. We never had a problem getting through, but we usually were only .5 -1.5 hours past our window and this was always early in the day (never past 3pm or so). I have heard of people having trouble later at night, closer to closing time, when alot of people may be coming to the fast pass line with over due times and the fast pass line starts to have a wait. I don't think it would be a problem in the morning or afternoon.