My first OLFA endurance lasted incredibly long. I was so impressed. I decided that is all I would buy from now on. The next blade was exactly like the basic blade and did not last nearly as long as the endurance blade. I find that odd. Since I keep a notebook of items I sew, I was able to see there was definitely a difference. I sent the blade back to OLFA with a letter explaining the details. We will see what happens.