Let me start by saying they cut great and stay sharp for a while. I will update if I use it longer. I've drilled about 100 holes and am happy so far. Spring . until I started putting boobs in every hole. I usually have to insert plugs for a tight friction fit. But with them I can insert plugs by hand. So a sticker is a must. It's not a problem and for the money they are good, just wish they were a little smaller.