I'm an experienced traveler and often book flights way in advance because of using miles. The below glitch on the United site could really mess you up if you weren't triple checking.
Last November I booked roundtrip flights from Italy to South Africa for next week on United using miles on Ethiopian Airlines/South Africa Airways/Ethiopian/Lufthansa. Flight out of Milan at 9:15 PM. I normally check flights about once a month, then weekly about 4-6 weeks before, and daily the week of trip. We have received a few notifications from United about flight changes. But here's what is strange:
About 2 months ago, I checked reservation on the United website on my lap top and United shows departure at 11:15 PM Milan to FCO, then on to Addis Ababa Ethiopia arriving at 8:40 am. When I first saw this time (2 hours later than the original departure time of 9:15pm), I noticed I had a 10 minute connection time in Ababa. So I went to the Ethiopian website to look for other options before calling United. Ethiopian airlines showed the original 9:15 PM flight out of Milan. Then I checked the United App on my phone and iPad, and it's 9:15. Called United and asked them to confirm flight times, and 9:15 pm is the correct departure out of Milan. United still can't tell me why to this day, the flight times reflect 11:15PM instead of the correct departure time of 9:15 on their Website.
So advice to remember. Not only check the reservation on the airline you booked through, also confirm your reservation from the actual airline with whom you will be flying. You will need to obtain the reservation codes for the airline you are flying on from the airline (or website) where you booked (codes are normally are not the same). Often you need to call customer service for these codes.
Also a remember to check seat assignments if you obtained when you booked. Often aircrafts change, which wipe out your previous seat assignments.