[iMore.com]

If you've got an old iPhone, you might want to think about trading it in to save on a new one. Full story from the iMore Blog...

[Wotchered]

No ! I have paid for it and I don’t need to look at insulting offers for what will become a back up phone anyway.

[Annie_M]

This isn't "new" news. I've always traded in my previous iPhone. I've traded them in at both Best Buy and at my carrier. I have found that I get a better offer from my carrier than Best Buy, so when it comes time to get my next iPhone, I'll check with my carrier first.

[Up_And_Away]

This isn't "new" news. I've always traded in my previous iPhone. I've traded them in at both Best Buy and at my carrier. I have found that I get a better offer from my carrier than Best Buy, so when it comes time to get my next iPhone, I'll check with my carrier first.

This!
Unless you want to keep it (backup, umm nostalgia), trade it in for discount on the new purchase. I’ve done trade ins with the Apple Store and the carrier, trading in iPhones, iPads, watches. My stock iPhone 11 got me 200 off 14 Pro Max. IPad mini 4 got me 170 off iPad mini 6. Definitely definitely trade it in.

You likely don’t get top dollar. Private sale can be 20 to 40% more. But trade in is super easy, convenient and efficient. I choose that path but totally understand a bigger money private sale.