Rather than “rethinking possible,” AT&T is rethinking its plans, as it becomes the latest wireless carrier to offer customers the option to upgrade their phones more frequently. Starting July 26, AT&T will offer new “Next” plans for smartphones and tablets, on a post-paid basis. The plan allows customers to trade in their devices (feature phones excluded) every 12 months, provided the customer pays a monthly installment fee based on a 20-month cycle. So, you would take the full retail price of a smartphone or tablet, divide it by 20 and add that cost to your monthly traditional or family-share AT&T plan. Twelve months later, you trade in that device for a new one, and a new cycle begins. If you decide you want a new phone before the 12 months is up, Next owners still owe the cost of the remaining months’ fees.