United Airlines is changing its loyalty program to remove mileage expiration dates. Effective immediately, the carrier is allowing earned miles to live indefinitely in MileagePlus accounts, granting loyalty program members permission to access and use them years in the future.

The move is a stark departure from the current constraint that American and United apply to their loyalty programs; up until Wednesday, both carriers put expiration dates on the miles that frequent flyers earn. If a traveler earned a few miles on a flight from Chicago to San Francisco, for example, the member had 18 months to spend the miles without the carrier taking them away. Any account activity — whether it be points earned from a flight or a partner program — also extended the expiration date of the miles.

Now, United is taking that expiration date away, meaning that miles earned today can theoretically be used 20 or 50 years from now.

On the surface, the change to MileagePlus is is good news for frequent flyers who for many years have tolerated cutbacks and tightening around airline loyalty programs. Not long ago, major legacy carriers in the United States generously ran loyalty programs in which miles never expired — but through much of the past decade, those programs have contracted, instead focusing on high-spend and millennial travelers (the only carrier that bucked this trend was Delta, which never put an expiration date on its miles). What MileagePlus members have thus earned in Wednesday’s announcement is in many ways what they had years ago when the program was more generous.

Either way, the change to MileagePlus is another loyalty milestone in what’s become a hotbed of activity at the carrier. Last summer, United’s new loyalty boss relaunched the cobranded United-Chase credit card and prophesied big changes to the upcoming MileagePlus loyalty program. In April of this year, the carrier formally announced that it is moving MileagePlus to demand-based pricing in November, a system that slides award seat prices up and down as a function of demand. And just last month, United invested in Clear and extended security screening benefits to its top-tier MileagePlus members.

All of United’s changes may indicate that it’s carefully placing a higher priority on broad consumer loyalty at the company – not just for millennial or high-spend business travelers. And as the carrier continues its quest for expansion, those everyday loyalty members are going to play a larger role.

Grant Martin [gm@skift.com] curates the Skift Business of Loyalty newsletter. He is also a director of product marketing at TripActions. Skift emails the newsletter every Monday.

Photo Credit: United is removing its expiration dates from its frequent flyer program. Bloomberg L.P.