Interesting that all four of these programs require a deposit of new miles/points. AA, UA, US and I believe DL all say that any account activity -- earning or redeeming miles -- is sufficient to keep your account active for another three years.
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by liveforflying:
In case they expire, what are the ways to have a small/least expensive way to create any activity in the account ?.
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If you want to play it safe and have some mileage deposited in your Continental account every 18 months (or your NWA account every 3 years, etc.), the cheapest way to do it would be to buy something small through one of their shopping partners. Especially good is something that doesn't charge for shipping, such as a gift certificate.
A very cheap idea comes from some diligent bargain-hunters in the SPAM forum, who found a
$1 e-book from Barnes and Noble, no shipping charge since it's electronic. B&N is a shopping partner of both CO (5 mi/$) and NW (2 mi/$).
Idine is another possibility, although if you normally send your Idine miles to another airline it's a minor hassle to switch to CO/NW and back.
Another simple method would be to credit your next car rental or Hilton double-dip to your CO/NW account.