When renovating our farmhouse we drilled several holes of different sizes in thick stoneware tiles. The trick to using these diamond hole saws is to keep the field wet while drilling, keep the hole saw and base cool, and avoid excessive pressure. As long as you don't overheat them, they'll last a lot of holes. However, if you overheat them badly just once, buy a new one. At first I thought the drill guide was a gimmick, but once I get the hang of it it really keeps the hole saw from rolling away. The best way to do this is to use a portable drill or drill guide, but in a pinch the included accessories will suffice.