Some do for sure. We all got new 6S's when we moved from AT&T to Verizon. My daughter's 6S was junk. Battery life was horrible and it would lock up almost weekly. Neither mine nor my wife's showed any of these issues. So we decided to let her get a 7.

But when I took her to the Verizon store I had the sales girl, and she got a kick out of this, bring out 3 phones and let my daughter pick the box so if this one was bad she's the one who picked it. LOL.

Much more stable phone, I just don't like the haptic "button".