Review on COS091509 Easycut Retracting Cutter Blades by Carol Miller

I cut and open many boxes as a retail manager. I needed blades for my personal utility knife because the ones they offer are rubbish. I've seen reviews of these blades and thought they were good, but if you plan on doing a lot of cutting these blades dull very easily and quickly. Sometimes I'll go through the entire sleeve (i.e. 3 blades) in just a week, which seems a bit quick to me. Overall, they're not bad, but they're not great either.