Check the regulations for your airline's reward program to determine the expiration date. This is found in the material you received with your card or on the airline's website under Terms and Conditions or Rules.
Buy a flight or use the card at a partner company to earn more points. Most airlines join with retail and grocery stores, car rental companies and hotels to give you opportunities to increase your points.
Buy more points from the airline. Most points programs allow you to buy points for a small fee. For those airlines with a rolling expiry date, this will extend your date.
Redeem your points at the airline or a partner. By cashing in some points, most airlines will extend your expiration date. Depending on the reward you choose, this may only require a few points, having little impact if you are saving for a big trip.
Donate points to charity. Many airlines assist organizations such as Make-A-Wish, the American Red Cross and March of Dimes by using donated miles to fund tickets for families, volunteers and staff in need. Your donation extends your expiry date and supports a good cause.
