So far the burrs show no signs of wear at all, but that’s with limited use. That’s why I started using them with oil, but from past experience I never used oil and the others I have are sharp so....... and yes a set of 10 various shaped burrs for about $18 and extension for $10 Not bent or chipped and still good for other use seems a pretty good value to me. What else are you going to use a 6 inch single cut Bent and chipped burr for?