My min schnauzer has been on SD for 3 -4 years now. I think dogs are only supposed to be on this for a month or two, but I have discussed with my bet. Regardless, she continues to develop stones while taking the SD. We have changed diet, water, everything we can think of. Currently she has 10 quarter size stones. At 12 years and three surgeries to remove them, I have gone holistic and have been treating her stones with herbs. It took six months but 10 stones have been reduced to 4. I am lucky to have a female. Male dogs don't have the luxury of time. Surgery is not the only option, but it is one I have chosen three times already. The herbs do take time, but depending on the size of the stone, maybe not as long as it took for ours to dissolve. Good luck and please feel free to contact me if you have questions. I have no medical training, I just love my dog, don't want her to suffer and have spent a lot of $ and time learning all I can.