American Airlines AAdvantage miles now expire 18 months after you earn them unless there’s some activity in your account. You can reset the termination date by either earning or redeeming miles, which means that there are dozens of ways to keep your miles fresh for your next award flight.

Here are some of the ways you can keep your AAdvantage miles from halting:

Use a Co-Branded Credit Card

If AAdvantage is your main frequent flyer program, it makes sense to apply for one of its co-branded credit cards from Citi. Anytime you make achase using your Citi AAdvantage card, you’ll earn AAdvantage miles. Those deposits reset your account’s expiration date. There are several branded credits available for individuals and businesses.

Fly

You’ll earn AAdvantage miles anytime you fly through American, and that will reset your account. You can also earn AAdvantage miles when you fly through any oneworld alliance member airline or any of American’s individual partners, such as Air Tahiti Nui, Alaska Airlines, Cape Air, Etihad, Fiji Airways, Gulf Air, Hawaiian Airlines and Seaborne Airlines. Just make sure you select the right frequent flyer program to reward when booking your ticket.

Buy, Gift or Share Miles

Buy, Gift or Share Miles

Anytime you buy, share or giveaway AAdvantage miles, your account’s expiration date will reset. You can purchase as few as 1,000 miles for $29.50 plus a $2.21 Federal excise tax and a $30 processing fee. This is not a cost effective method of resetting your mile termination date so use this option as a last resort.

All of these methods of earning miles will reset the termination date of your AAdvantage account. Don’t forget that any time you comply miles, that activity will also reset your account. Every single mile is valuable, so keep tabs on the date of your last activity and don’t accidentally lose miles.

As a last resort, you can pay to have your lost miles altered. AAdvantage charges $200 to reactivate 1 to 50,000 miles, $400 for 50,001 to 75,000 miles and $600 for more than 75,000 expired miles.