Originally Posted by fti
I love how "mileage does not expire" but if you have no activity within 18, 24 or 3 months your "miles that don't expire" will indeed expire.
Technically, it's not the miles that expire. The account is closed for inactivity. Of course, the miles that were in it disappear when the account does, but it's not exactly the same thing. Miles can get a lot older than that, in programs that follow this approach, as long as the account remains active overall.