Durability is determined by the inability to handle shipping as the discs are badly damaged on arrival. The tool is not held securely in the box and will dangle loosely during transit, resulting in dents, dents, and damage. For the price I figured they wouldn't last long, but long enough to make a bearing set and then throw it away. I should note that this is the second set after returning the first set which arrived without a handle. Considering this is a tool that will be hammered and eventually hit, I can't justify paying more for what I'll be hammering.