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My daughter is using my old 6S and it is finally starting to show its age navigating through iOS 12 and running some apps. I would not recommend one now.

This is the excuse I have to upgrade again this year :) my wife can have my X and my daughter can have my wife's 7. The 6S will be getting retired.
 
My daughter is using my old 6S and it is finally starting to show its age navigating through iOS 12 and running some apps. I would not recommend one now.

This is the excuse I have to upgrade again this year :) my wife can have my X and my daughter can have my wife's 7. The 6S will be getting retired.
Sell the 6s on Craigslist or something. While it still has an value at all. You might get $200 for it.
 
I went with a 6s Plus on eBay for pretty cheap. The headphone jack was one "feature" I wanted. I use headphones and a stereo a lot. I tried Android (Pixel 2) for a year and wasn't that impressed. The 7, 8, and X don't have anything more I really need although they are obviously slightly better/faster/improved camera.
 
No question, get the iPhone 7. The taptic, force-sensitive home button on the 7 is way better than all the previous mechanical home buttons. Also, faster chips. You'll be happier with the 7, guaranteed.

One other thing, I actually like the sound quality of the lightning cable with wired headphones, even with having to use the adapter. I use the phone quite a bit, so audio quality is important. Sometimes had problems with iPhone audio jacks, but thus far lightning connector + wired headphones has been flawless. (Hate bluetooth, even in 2018 wired sounds superior in every way.)
 
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