Previously, United miles expired after 18 months of inactivity, though it was possible to keep them active by earning or burning miles — even for items like magazine subscriptions and donations — before the expiration date. Additionally, customers with a co-branded card didn't have to worry about miles expiring as long their card account was active.
While MileagePlus members don't have to worry about miles expiring anymore, that isn't the case for the majority of other programs. American AAdvantage, Alaska Mileage Plan, Southwest and other top carriers around the world have expiration policies, though it's generally possible to extend the date — without the need to fly.
