KNOCK ON WOOD, it has been 10 years since my last bad one / get to the ER NOW stone! Had my first one in Nov 1993. I was told by a urologist that anybody can have one but if you have 2-3 +?? HANG ON! All of mine have been calcified. I USED to drink a TON of sweet tea. That did not help. There is a large stone that has been lodged in the center of my right kidney for 7-8 years but it is not going anywhere. It has been about 5-6 years since even a small one so I am HOPING my system has adjusted and I'm done.