They DO break. But that's in childcare, after a loooot of use. Loss of magnet was not so much an issue in that setting, I never had it happen, but when the magnet gets a bit old you have to get it in exactly the right spot. Also, repeated use can wear down the surface and leave a mark. But again, that's childcare, maybe more intensive use? Hard to say. Anyway, definitely effective, definitely reduce finger jams.