In 30-year-old concrete, I first tried other masonry drill bits with battery-powered impact wrenches to install latch boards for new decking. It did not work. I relented and rented a rock drill from Home Depot and drilled 50 holes - pretty quickly. It wasn't quite like butter, concrete drilling takes some effort, but each hole was drilled in less than a minute. I didn't notice any more effort or time on the last hole than on the first. I guess if I had to complain it would be that I didn't need five drill bits for my project. I think there's a lot of life left in the first one.