I've been using them for almost 10 years (when they first appeared). They are brilliant and work very, very well. I've never lost a magnet. I think the only time I lost a magnet was when I forgot to take the corset out of my shirt when I took it to the dry cleaner. Found one and lost the other. The reason I came back for more was because I wanted the 2" versions when my 2.5" versions were. Just needed shorter ones. These new ones now have a magnetic rubber pad on one side. I've only worn them once but when I rearranged the posts I felt the magnet didn't slide into the collar as easily when the rubber made contact with the fabric. They may have done this to reduce glare in case someone sees the magnet in your collar; I do not know. But I've never had a problem with metal buttons. Otherwise 5 stars.