Q. I need to preserve some United Airlines MileagePlus frequent flyer miles that are due to expire soon, but I don’t have a United credit card and I don’t plan to fly on them or on a partner airline any time soon. Any suggestions?

A. There’s no excuse for anyone to have miles expire. Most airlines have shopping mall sites where they will award you anywhere between 1 and even up to 24 bonus frequent flyer miles for every dollar spent (that’s in addition to at least 1 mile per dollar charged on a frequent flyer-affiliated credit card). So, for example, if you spent $10 on drugstore.com, walmart.com, or hundreds of other merchant web sites, not only will you get bonus miles, but you will preserve any expiring frequent flyer miles. Airlines also have dining programs, which you can register for and when you dine at participating restaurants, you get bonus miles and also preserve miles. Since almost everyone shops or dines out, this is a great way to extend the life of your miles. You can use any credit card to make these purchases. For more information, check out our recent blog post on the subject.