The stainless steel stones will last a lifetime when properly cared for. If they seize on you, there is hope. After 7 years of heavy use on my 0.5 micron stone, boiling in water after each use and a forced air dry, it finally clogged completely. I thought all was lost, but I made a fairly strong PBW solution and boiled the stone for about 5 minutes, then rinsed it thoroughly and it completely came back to life. In fact, it works so well now that I realized it just became progressively more clogged over the years and I just never noticed the decline in performance. I'm putting the PBW boil as part of a regular maintenance item.