The battery has a lifespan and eventually needs replacing as well. Not sure if that falls within the scope of physical damage, its subjective I guess. Even routine charging could count as maintenance. What about cleaning the screen (to get fingerprints off the screen)? Surely that counts as maintenance too? New wifi & cell protocols could be invented that also render it obsolete. If you run out of space on it, old files aren't automatically pruned... going through my photos deleting stuff counts as maintenance I'd say. I've also had it become frozen / sluggish and had to reboot (even with iPhone 6)