I have heard many replace their phones due to dropping them and becoming unusable. But everyone uses a case now and the build quality is generally better that one mishap does trash the phone. Most people I know getting new phones now did so bc their old phone "got too slow to be usable." I believe that's a matter of new OS versions really are much heavier. Both my last 2 phones I had upgraded bc I went one version too far and had a nearly bricked phone.