The bits are single use but in one project I burned 3 of them and now they are garbage. Two of them lost their bearings (twice, and eventually the bearing fell apart) while I took advantage of them and scratched the workpiece, and the other had a bearing that just froze and blackened the edge of the tree. Although I've only used them once, I bought them months before I started my project so my return window is long gone. If the company comes forward and offers new beats or a refund, it will make a world of difference.