Have you thought about getting a blade sharpener. I use one and have gotten many more uses out of my blades before I have to replace them. I believe mine is a TrueCut and you run the rotary cutter through it a couple of times to sharpen the blade. There are other brands out there as well.

Make sure you close the cutter between uses (also safer). When I am finished sewing for the day, I store my rotary cutter in a case which looks like an eyeglass or pencil case. I also use a soft "cover" that velcroes over the blade mechanism (wish I knew where I got this as I'd love to get others) before I put the cutter into the hard case. I find that by keeping my cutters closed and stored keeps them sharper longer. Don't know why other this works, other than the blades can't "hit" things accidentally and dull them. I don't change blades until I can't cut cleanly through fabric. Many of my blades have lasted months with no skipping problems. I only use the Olfa 28 mm blades. Don't like the Fiskars as much (will use if I have to) and absolutely detest the Harbor Freight (never got a sharp one). JMHO...

That is my thought too. If you do a lot of cutting I would expect to change the blade more frequently but the condition of the mat may also be a problem.
peace

I have been using blades from Harbor Freight. They aren't easy to get off the card, but I rub oil on them, and they are great, and so cheap.