Your workshop manual will tell you the recommended intervals - it can be anything from 30,000 to 50,000 miles or even other mileages, but don't try to economise! If you're in doubt, or you've bought a car / van and you don't know when it was last changed, do it! a belt costs about £14, but if the old belt snaps it will wreck your motor and cost you however many hundreds it takes to replace a trashed motor. Even if you have to pay someone to do it for you it's worth it.
DaiTheVan, August 2005
