Our unique sharpening system has created a blade that is in for the "long haul" especially when used with the Martelli’s Ergo 2000 Rotary Cutter and Tri-Co Professional Mat. The life of the blade will last approximately 5 times longer. To replace your blades, first unscrew the bolt by turning it in the direction of the arrow. (This will be the opposite direction you may be used to - this keeps the bolt from unscrewing as you use the cutter. Carefully remove the used blade. Slide the new blade back into the cutter. Insert bolt and tighten securely by turning the bolt in the opposite direction of the arrow. NOTE: On a right-hand cutter, the bolt will tighten to the left. On a left-hand cutter, the bolt will tighten to the right. Make sure you discard all used blades in a safe manner. A preferred way is to wrap them in paper and tape closed. Please do not merely through them in the wastebasket!