From LDH Scissors:
Every one of our 45mm Midnight Edition Rotary Cutters comes with one blade and packed in a reusable felt bag, eliminating unnecessary blister/plastic packaging.
This can vary person to person and how one uses their cutter, as well as the type of cutting mat they have. We tested our blades at various fabric shops in Toronto, and after using them for up to 8 hours a day, five to seven days a week, each shop got between 3 - 4 months of use from one blade!
The cutter can also be easily switched for left-handed users. Simply unscrew the bolt, slide out the blade and place it on the other side of the cutter, and tighten the bolt back on.