Crimp beads are made of metal, and eventually, the metal will wear away at the elastic and cause it to thin and break. You can tell when this hasn’t been done because the beads may be a little loose or the bracelet stretches a bit the first time you pull on it. When the elastic is pre-stretched, it will snap back to the same size without losing any of its elasticity. The beads should be slightly tight against each other and keep a slight tension on the elastic—and therefore the knot—preventing it from loosening during normal wear. It usually means the knot has been glued and the glued knot secured inside a bead. This will protect the knot from the type of chemical breakdown. Also, the glue can sometimes harden the elastic and keeping it securely inside a bead will lessen the stress that it is exposed to, making it less likely to fail. The only suggestion to limit the occurrence is to wear your bracelets on your non-dominant hand. For righties, wear them on the left and lefties, wear them on the right. You are much less likely to get your wrist caught on something with the hand that you use less often. This type of thread will eventually fray, with individual strands breaking free over time until there is a complete failure. It doesn’t mean you should avoid these bracelets or this material entirely, just make sure you’re aware when the bracelet uses floss and look for signs of wear and tear. Note that gossamer floss should never be used with sharp gemstone beads, crystals, or heavier beads since all of those are likely to limit the lifespan of the stringing material.