I'll replace ALL of the tensioner parts if I'm going to be in there....
Good idea, really. I've had failures of _all_ those parts at one time or another, and on only two cars! The rocking bearing, though stout, really takes a beating and doesn't hold up well. The spring can break. The shock can break and/or wear out. The idler bearing can dry out and/or seize. The idler pulley can be worn to a nub. And don't forget the two plastic caps that go over the two bearings to keep the dirt out. And pay particular attention to get the big bolt that holds the tensioner to the timing chain vault torqued correctly. If it works loose it'll ruin the chain vault cover. You won't like that. -- Jim