I am trying to decide if trading in last year's purchase makes sense or if I should keep it as back up instead. Here's the scoop. I bought iPhone 6s Plus last year as the 7 did not impress me at the time. Back then, I got the deal from T-mobile where they basically pay half the phone through monthly credits. I have $330 left on the plan. If I trade the phone, I have to pay off the $330 and the credits (about half of that amount) will stop as well. So, I am giving up about $165 in credits up front. I then get $300 trade in ($155 up front and the remaining $145 in monthly credits over 24 months, so about $6 a month). Of course, I have to trade in last year's device. Option two, I learned that T-mobile will allow you to have more than one hardware payment plan per line. So, I could just buy the second phone and keep paying for the 6S (another 12 months). Then either keep it for back up or use it as trade in then or sell it... whatever. Last option, hang onto it another year and forgo the update all together. Battery issues will improve (hopefully) and the upgrades are not worth option one or two. Any recommendations on what I should do?