I am on my second set. My first set had one come out in the back. I had a new set made at the time. My dentist and my insurance pay for a new set every 5 years. This set fits much better than the first set fit. It may be a while before I do another set only because my dental practice closed when the dentist retired. So as long as these are doing well I will stick with these. They are sound and working well.