I've got half a memory of a old Car and Driver issue where they got to play with a great big Caterpillar bulldozer; Metal fatigue rendered them all disposable within a decade. But This Is Battletech, so I don't know what to do with that data point. Does stuff that should wear out benefit from the funny reinforced structure mechanic?
Then, do you make a distinction between damage from wear, and enemy fire? An executive summery of pp.166StratOps would lead you to do what? :-\