I used them to hang 3 towel rails through real porcelain stoneware which is very difficult to get through the outer layer. I don't know how long they should last, but I've used them all. I could probably poke a few more holes, but not by much. They were very sharp and this made it easy to plug the hole without bouncing. I was happy with them. I know you should use this look for this type of hard tile. If I lay tiles again I will buy them again to make sure I have good mounting holes. and don't ruin the tiles.