Repairing Ripped Belts
Sanding belts can rip at the worst possible moment – such as when you're out on a jobsite with no spares. When this happens I remove the belt, turn it inside out and cut the torn spot into a diamond-shaped hole with a utility knife. This adds life to the belt without affecting its performance.
Even if I did have spares I'd still use this technique just to squeeze every bit of life out of the belt. I don't get why you'd have to turn it inside out, though.