When you fly you earn airline miles. They used to be based on the distance of your flight. Now the big three airlines in the U.S. — American, Delta, and United — all switched to giving you miles based on your ticket price.
The miles you receive are not free. They are included in the ticket price you pay. You pay a little more than you otherwise would today for a possibility to get free travel in the future.
Among the three airlines, Delta does not expire the miles you receive. American and United would wipe you miles clean if you don’t generate some activity in 18 months. Southwest expire their points after 24 months of not earning any points. If you are not careful, you can accumulate many miles/points and then see them forfeited. Some airlines can restore the miles but you will first have to pay a hefty fee.
An easy way to keep your miles active is through the airline’s online shopping portal. Almost every airline has it. Most of them are all run by the same company behind the scenes (Cartera Commerce, now part of Ebates). You first log in to the online shopping portal. Then you pick a listed online retailer. You order from the retailer as usual. After your order completes, the airline receives a cut from the retailer for sending you there. It uses part of the cut to give you some miles.
The everyday type of retailers are covered by the airline shopping portals. Walmart, Target, and Home Depot all offer in-store pickup with no minimum order size. To me the purpose of using an airline shopping portal isn’t to earn some extra miles. It’s more helpful to prevent your existing miles from being forfeited. The 10 miles added to the account extends the expiration date by another 18 or 24 months.
The miles earned from the shopping portals post relatively quickly, which can be as soon as in a few days. If you see your miles are about to expire, put in an order through the airline’s online shopping portal. In case you forget, maybe set a recurring calendar reminder to do it once a year.
Airline miles accounts are in individual names. If you are married and both of you have miles, remember to use the shopping portals with separate accounts to keep both accounts active.
Links to a few portals: