Q. We are hoping to book a flight to Australia for next Christmas, and currently have about 270,000 miles accumulated with United Airlines. We were curious about upgrades, but heard somewhere that upgrades aren't allowed until the day of or day before your flight. According to United, it's 30,000 miles to updgrade to the next class of service - so if we purchased Economy seats, I'm assuming we're okay to upgrade to Business? Just wondering if you could clarify how this upgrading works, and if you think it's beneficial to do so on such a long flight!

A. On a flight from the US to Australia, it will most certainly be worth it to upgrade. The way to go about this is to make sure you book your trip on flights that are available for upgrade (flights that have seats in the upgrade "bucket"). You can call United and ask them to search for such flights, purchase the economy fare, and then immediately have them pull miles from your account for the upgrade. I went through this process recently and they didn't charge me to deal with an actual human. Not sure if that's always the case, but I'm not an upper tier member of MileagePlus.