Avoid missed flights and getting stuck in a middle seat. Always confirm your flight info the night before your trip – better yet, a few days before. When booking your flight weeks in advance, the departure time may change from what you originally booked. You do not want to arrive at the airport only to find your flight left earlier than you thought.
The plane configuration may also change, resulting in a middle seat that you did not expect! (Tip: many frequent fliers get upgraded into first class in the few days before a flight, so you may have a chance to move out of a middle seat as their coach seats become available.)
Validating your flight a day or more ahead of time gives you a chance to contact the airline online or via telephone to address any seating, timing or other ticket issues.