T-Mobile will now let customers carry over their unused cellular-data allotments.

U.S. wireless carriers have been pushing consumers into larger data plans, but they typically lose what they don’t use at the end of their billing month. Under T-Mobile’s plan announced Tuesday, customers would be able to stash what they don’t use for up to a year. It’s reminiscent of the days before wireless companies offered unlimited voice calls; some carriers were offering to rollover unused minutes into future months.

T-Mobile says that with its plans, customers won’t have to guess how much data they might need. If they buy too much, they can save it. This approach also helps customers who might not use the same amount of data each month. Watching video while traveling — without the benefits of Wi-Fi at home or work — can quickly use up the data allotment, as a two-hour movie can easily consume more than a gigabyte.

The program is open only to customers on Simple Choice plans with at least 3 gigabytes for a smartphone or 1 gigabyte for a tablet. Eligible customers won’t need to do anything to participate. Customers will also get a one-time free allotment of 10 gigabytes when the program starts next month.

T-Mobile likened the practice of losing unused data to a grocery store clearing out what you don’t eat each month.

T-Mobile, the nation’s No. 4 wireless carrier, billed the new program as the company’s latest “Un-carrier” move. It’s a term T-Mobile uses to describe programs and plans that shatter longstanding industry practices. Past announcements have included replacing two-year service contracts with phone installment plans and letting customers upgrade phones more frequently than every other year. Rivals have since adopted parts of those programs.

But T-Mobile isn’t alone in offering data flexibility. Other carriers do it by letting families share a collective pool of data within a given month — so Mom can be a data hog one month, while Junior uses a lot of data the next. T-Mobile does not offer data-sharing plans, and its family plans require each person to manage a separate allotment of data.

(AP)