I started buying Levy's cotton straps when I couldn't find Earth III straps anymore; about 15 years ago and have some of the same ones today as I did then. I've never broken one with any of my basses. The only real complaint I have is in the length. The only way to you get the length in Levy straps that you get with Dunlop or Earnie Ball, is if there's an "XL" in the model number. I make it a point to grab a Levy XL whenever I see them, because I don't come across them often. I prefer poly straps over cotton because I like the way poly straps move. Cotton is a good happy medium between poly straps and leather ones.