I had to run out and try these as soon as they arrived. I used the same blade on several different kinds of plastic and on several different kinds of wood. The blade didn't seem to dull during the time I used it and it did a great job cutting. I did try it on metal and that didn't really work out very well but I didn't expect it to as it says on the blade that it's for wood and plastic.I love the fact that I got 100 of them in a box for way less than I've been paying at the local hardware store. There I pay from 5 to 10 dollars a piece so 100 of them for $40.00 is a real bargain (that breaks down to 40 cents each). Heck at this price I still come out ahead even if they only last 1/4 as long as one of the more expensive hardware store bought blades.However, based on my using the same blade on multiple different things I guessing that they will last almost as long as a more expensive blade.Great buy for your shop and it's great to have enough of these so that when I ruin one I won't have to run out and buy another one.