I'm a fairly new user with a 24" silver bullet. I used my first 60 degree blade forever, it seemed, but it became clear that it was dull, so changed the blade. Got an inch or so of clean cuts, then started getting terrible corner cuts. I thought maybe I had somehow chipped my blade, put a new one in and was fine for a second forever ( 41 yards of wallpaper ). But, I had to change the blade again and the same thing happened. Twice. My guy got out his handy dandy magnifying face shield and I'm definitely chipping the tip off the brand new blades. We could see the difference between a blade that was simply dull and the brand new one with a broken tip.
I'm cutting a painted wallpaper blank stock (wall liner) that is a non woven polyester material. About the thickness of cardstock, but not as dense. I do use a homemade 6' mat out of a harder polycarbonate than the Silver Bullet mats. I think the first blade I broke was due to not reducing the force a bit to compensate for the new, sharp blade - but I did adjust on subsequent changes. I'm cutting at a force of 70, which is what I seem to need to get a clean cut on this material.
Any suggestions, thoughts or wild guesses are welcome!