Abe,
CBS
On the fifth year and each yoear after the belts are to be tested with a magnetic flux leakage tool. If the show the belts are worn, they are to be replaced within six months. If they are bad, replace them immediately.

Pulse
A Pulse test is performed to measure the resistance of steal cables in the jacket during a learn run. When the resistance drop below the recommended level, it is time to replace the belts.

I would love to see the hard numbers on how costly and or cost effective theses belts truly are!