I change blades at first skip and don't use much pressure to cut. I cut the fabric not the mat. Using a weighted rotary cutter like Quilter's Select works for me. Not much pressure is needed. Buying new blades or a new mat equals out so it's personal preference. I have taken classes from many top notch quilters who use the mat line for cutting if they aren't promoting a ruler brand. When I see a mat on a good sale I buy it. I stack them on my cutting table (right now I have a stack of three) and rotate from top top to bottom and turning the mat when I think of it. I'm always using a new mat this way for a very long time.