Join Date: Dec 2005
Location: Market Drayton, Shropshire
Car: MGBGTV8, BMW530d, Suzuki GS1000
By the time the belt has visibly deteriorated, you would be lucky to have an engine still running. Broken belts usually look perfectly OK (apart from the break of course). If you have a look at your belt, check for any perishing of the rubber surface. Check for any of the fibre reinforement coming away at the sides (the reinforcement is usually visible as a white "stitching" on the side of the belt. This is normal - having loose strands is not!). Check the belt teeth where they join onto the belt. There should be no cracks whatsoever at this point.
As your car has now done 70k, for peace of mind I would change the belt, tensioner and water pump. Yes, it will cost money, but not anywhere near as much as if any one of those components fails.