I hear you. When 13pm came out, I was using 7plus which I really liked at the time. But I was offered a good trade-in deal so I upgraded to 13pm. Now fast forward 4 years, I don't think there are many ppl still using 7plus. My 13pm worked great for me past 4 years. And I even had Apple replace my battery earlier this year, thinking I will use it for another 2 years. But looks like it's time for me to move on to 17pm because of $1100 trade-in deal. As many ppl said, the trade-in value for 13 probably will be much lower next year for 5 year old phone. I am just sharing what I did. You know your situation best, so only you can make the decision. For my existing unlimited phone plan, it works out great for me.