Starting August 6, the carrier is moving to 36-month device payment plans, replacing the 24-month option it has offered for years. If you’re planning to switch to T-Mobile or pick up a new phone soon, this affects your monthly bill and how long you’re stuck paying it off. The new setup can lower what you owe each month, but you’ll be making that payment for an extra year. It lets approved customers roll the phone’s price, taxes, and setup charge into one monthly payment with nothing due at signup. Shopping for a new phone with T-Mobile after August 6?