If you are going on a trip 1,000 miles away and it takes exactly 14 hours to get there without any traffic etc. Would you leave 14 hours before, or give yourself some leadway?
The same should be done for flying. As stated above delays happen all the time at the airport. If you can spring 10k to go on a cruise, but you can't spring 100 bucks for a hotel for a night, then don't blame the airline when you miss your 10k$ cruise.