Mine would be rotary cutting blades! I suppose that"s why I wait too long to change blades. I also know my cutting mats will last longer , so I guess it will work out in the long run.
Also patterns that the instructions are so minimal... I bought a pattern from a large online company for a tote ... as the zipper looked like something I had not seen that technique before... the pattern was one sheet of regular paper.. no visual diagrams .. and when it got to the zipper ... it said "insert zipper in usual manner"!