I agree:
- how old is the blade?
- is your blade a knock off brand or ?
- are you using only 1 blade?
- what condition is your mat in?
- how many layers are you trying to cut?
Personally, I can only cut 2 layers at a time. But, that's me. My favorite mat is the Martelli brand. It has lasted the longest and I think the blades last longer with it too.