Constant use is a negative for airplanes where metal fatigue builds up over use. eventualy it is cheaper to scrap an old plane than to replace every part that might be nearing end of life.
One of the fun facts about airplanes is that they are made almost entirely aluminum. And, if you go, look it up or talk to a mechanical engineer, you will understand that aluminum has no “fatigue limit“. That sounds like a good thing, but it’s not. Aluminum will always fail eventually no matter how small the load. It’s just intrinsic in the material.
