Comment by frollogaston

I've owned multiple iPhones that I've kept for a long time. The iPhone 6 was the only one that shut down randomly, and the phone was only 2 years old then, so yes it seemed defective. After it did that once, it got throttled to the point of being nearly unusable for several months until Apple pushed an update to let me disable that.

Most users seemingly responded by just buying newer iPhones that didn't have this problem, before Apple even offered the $29 fixes. I got an old iPhone 5 instead, and it was fine. So I'm pretty convinced the 6 was just bad.