I found years ago that the blades seem to last longer on the self healing mats. Also, flip your blades as you can get a bit more out of them that way. I have a blade sharpener so I get a bit more life out of them that way also. Once I've sharpened them once, I sharpen them one more time to use for cutting paper only. I have my rotary cutters marked for either fabric or paper so I don't get them mixed up.
Also, I use the 60mm most times. But whatever size you use, be careful. Yesterday I thought it would be great to try to slice a bit off on my right index finger. Bled like a stuck pig. You don't realize just how much you use your index fingers until you can't. Luckly it was my right index and I'm left handed but still troublesome like trying to type right now or use the pc mouse.
Also, try the titanium blades, I think they last much longer and less expensive too. Think I ordered tehm on Amazon.