To avoid excessive wear on your Rotary mat, don’t cut repeatedly in the exact same spot. When your mat becomes nicked and worn in the area you use for cutting, flip it around and use the opposite side or end. Using a clean, unmarked surface will double the life of your mat AND your blades.
You can also use the back of your mat. And remember, don't leave your mat sitting in the hot sun, in a hot car, or put it near a heating source. Your mat will become warped and will be useless and dangerous for cutting.