With every program that changes its expiration policy, there is renewed interest in what exactly the expiration policy is for all the programs. We’ve rounded up some of the larger airlines’ policies below. Note that we are using the actual wording from the various programs’ Web sites. Also, the policies of American AAdvantage and Northwest WorldPerks is similar to what all these programs had just a few years ago.

We should also point out that members who are earning miles to keep their accounts active should pay close attention to what the airline is saying will qualify to save their miles — simply earning miles might not do it. For example, you might earn miles for filling out an online survey but because these are considered “promotional” miles as opposed to “partner” miles, or miles earned through flying, they could very well not count toward extending your mileage balance.

Air Canada Aeroplan:
Until June 30, 2007, miles expire in accounts that have had no activity for the prior 36 months (three years). Starting July 1, 2007, mileage will expire in accounts that have had no accumulation or redemption activity in the previous 12 months (one year). In other words, you must accumulate or redeem miles in your account at least once a year to ensure that your account stays active. So, if you have not been an active Aeroplan member in the last six months of 2006, you have until July 1, 2007 to either accumulate or redeem miles in your account to avoid expiry. Also note that starting Jan. 1, 2007, accumulated miles will be available for redemption for seven years following the accumulation date.

American AAdvantage:
Effective Aug. 4, 1999, your AAdvantage miles will no longer expire as long as you have qualifying account activity at least once every 36 months. Qualifying account activity is defined as any AAdvantage mileage accrual or AAdvantage award redemption.

Continental OnePass:
Miles currently have no expiration date; however, Continental Airlines reserves the right to impose expiration limits or terminate the OnePass program, plus terminating your ability to claim rewards. If you do not have activity in your OnePass account for a period of 18 months, Continental Airlines may close your account.

Delta SkyMiles:
Currently, miles will not expire as long as you participate in one of the following activities at least once every two years:

Earn miles for travel on a qualifying Delta, Delta Shuttle, SkyTeam or other SkyMiles airline partner flights.

Earn or redeem miles with one of the SkyMiles program partners including hotels, car rentals, Delta SkyMiles Credit Card from American Express, international credit card partners, SkyMiles Dining & Hotels by Rewards Network, MilePoint.com, mortgage lenders, CAP magazine subscriptions, real estate or telecommunications partners.

Buy miles here at delta.com or by calling the number on the back of your SkyMiles card.

Redeem miles on Delta, Delta Shuttle, a SkyTeam partner, or another SkyMiles airline partner. Redemption of previous program awards does not extend the mileage expiration date.

US Airways Dividend Miles:
Effective Jan. 31, 2007, active membership status is based on having earned or redeemed miles within a consecutive 18 month period. With our new Mileage Reactivation Policy, Dividend Miles members have an opportunity to reinstate their Dividend Miles accounts to active status for an additional 18 months for a $50 processing fee and reactivation fee of $.01 per mile. If members do not extend with this reactivation option, the Dividend Miles account will be closed and all miles forfeited.

Northwest WorldPerks:
WorldPerks miles have no expiration date. However, consistent with the general terms and conditions of the WorldPerks program, Northwest Airlines reserves the right to change the WorldPerks program at any time without notice, including imposition of expiration limits or reactivation fees. If no mileage from any source is posted to a WorldPerks member’s account for three consecutive years, the account is subject to termination, including forfeiture of all accrued mileage.