I haven't been careful at all about what I have cut with these blades, they are still sharp and no skips and its the first blade I bought and put in months ago. I have cut many feed sacks with them and they are like the little pink bunnie or a timex watch, keep right on ticking. They have been very good for me, in fact a lot better than the Quilt shop blades. I put them in and before the day is out they are skipping and dull. So yes I am HAPPY HAPPY HAPPY with them. Can you tell lol..