I flew out of Dulles for a weekend getaway to Vegas on March 29th. My trip to Vegas was as usual but the trip back on April 1st shows how United handles crisis. We were scheduled to fly back to Dulles on April 1st at 1:45 pm to be back at 9:10 pm. We got to the gate in time and started boarding with no problem. Once we got to our seats the pilot announced that there is a minor problem on the wing and it is being fixed and will take 15 to 20 minutes. We could actually see the mechanics working on the left wing. Typical right? After 20 minutes the pilot came back and announced that he had good and bad news. The good news is that the current problem is fixed and the bad news is that there is a new problem this time with the door not closing. He said that we need to deplane and we started heading out the airplane. We were told that the flight will be delayed by an hour and half. They were updating us by text, the updates keep coming delay by 2, 3,4 hours... Then they announced that it is a small fix and they are looking for the part in Vegas. The story changed and now they said the part is being flown from Houston. Nothing to worry about the agent keeps announcing, unknowingly contributing to our aggravation. 5,6 hours delay the texts keep coming. They finally decided to give us $10 voucher for dinner, hard to find anything priced under 10 unless you buy candy. For those that want to leave the terminal they started giving out hotel vouchers to south point casino. The problem with that especially for those of us where Dulles is our final destination, is that all the flights are booked the next day and we have to be come back to the terminal to be on standby, another nightmare. We decided to stick there because our schedule affects our family. The story changed again and they said that they are swapping the airplane, and the new plane is coming from Houston. Some showed relief, until another problem was announced. We have the plane but we could not find the crew. All crews reached their limit for the day. After some time we were told that they found a crew from California, and they were scheduled to leave San Francisco at 8:20 pm. The plane and the crew got together around 10:30 pm and we finally left Vegas at 11:10 pm after hearing aggravating announcement and annoying slot machines all day. We made it back to Dulles at 6:30 am. In my opinion United has poor contingency plan they keep creating stories until they find out what to do no plan in place. The flight should have been cancelled and rescheduled for the next day or late evening to give people the option to go outside. We stayed in the terminal for close to 10 hours.