My buddy at work has a T-Mobile iPhone 6s 64gb that he likes, but is a couple years old and the battery is poor. Per the settings, it says 84% but per coconut battery, it is 72% and 643 cycles. Cheapest path: replace the battery for $29 at the local Apple Store by the end of the month. Upgrade opportunity: go to Costco and upgrade to an XR 64gb. They sell it for $699.99 and have a trade-in promo where the 6s can be sent in for a $250 credit/gift card. So, while adding sales tax: A.) $31.17 to replace battery and keep 6s 64gb for another year or so or B.) $502.49 to replace 6s 64gb with XR 64gb For the record, I am personally happy and adapting to my own XR the past few weeks (even though I do miss the home button). Thanks!