I took my iPhone 6 in today for a battery replacement (purchased on release day 2014.)
Went back in two hours, had to wait an additional hour or so. No big deal, that's what the bar next door is for.
Went back a third time, ended up waiting five minutes because there was some issue with my repair. The girl comes out and says my old phone won't turn on after the battery replacement. Their solution was to replace my old phone with a brand new (not a refurb) iPhone 6.
My old phone had a missing camera lens, a non-functional touch ID, a third-party replacement screen, a non-working headphone jack, and a non-functioning earpiece.
Will I buy another Apple product when the time comes? You bet.