I used 6 or 7 different drill bits when drilling a cement retaining wall to install a wooden trellis tree mount. Each wears out after a short time. I could only use one bit for a maximum of two holes. Ridiculous. I decided to give it a try and am very happy with it! I've only used one that's still in perfect condition and halfway through the project. It's about 12 holes. HIGHLY RECOMMENDED!