labor is what kills your pockets, unless you do it yourself. another way of know if your belt is going bad is that, you'll hear the belt getting loose and hittin the cam gear cover. IF it's just loose, you can tighten it back up by adjusting the Timing Belt Tensioner, that's possibale if you got a manual tensioner. Tensioners also go bad, i've read that most of the ones that go bad are the automatic ones, i suppose that's why some people convert to manual tensioners. Also if a belt is loose, and skip, jump or hop, it can through off timing. Do some inspection first to determine if your belt really needs to be change, but like someone else state, the manual recommends you change it at a specific mileage.