I once did some volunteer sewing at a group where the "bossy" quilter had brought a cutting mat that was some kind of clear semi-hard plastic. She insisted everything be rotary cut on it and I watched a brand new fiskar blade go dull in a matter of 10 cuts. I'm wondering how many of us who find our blades aren't lasting well, actually have a problem with the mat underneath? Needless to say, she disgusted me and I quietly left. Meanwhile, nothing anyone cuts there is straight or on grain...imagine!