NEW YORK (AP) — AT&T’s wireless business had a strong first quarter as the company added more than 1 million subscribers and benefited from an installment plan that permits frequent phone upgrades.

Although customers in the installment plan, called Next, aren’t locked into traditional two-year service contracts, they pay the entire cost of phones in installments. As a result, AT&T doesn’t have to pay hundreds of dollars per customer in subsidies. In return, customers can get a new phone as often as every year instead of every other year.