In first use with a hammer drill, I screwed 8 screws of 10cm with ease into a wall to secure a heavy piece of furniture. Like butter! It didn't kick back even once! I believe they will withstand the test of time because I use them for amateur purposes, so it doesn't bother me, but they seem to be of good quality. Anyway, if you want to get your money's worth, get a hammer drill. It does all the work, the bits just assist.