most of the time is just saggy due to age and not worn parts
So as a component gets older it doesn't suffer from any wear?
It does suffer wear ofcourse, but the hinge pin being worn is less common than sag due to the weight of the door.
I would say hinge pin wear is a lot more common, my 5door had loads of wear in the top pin on the drivers door, you could lift the door up and down and see the play in the pin.