No prescription diet is complete and balanced though. It has to be modified form AAFCO nutritional standards to help manage a certain conditions. Doesn’t mean the diet doesn’t provide adequate nutrition or isn’t medically necessary. That’s why it’s a prescription and needs to be prescribed judiciously by a veterinarian. In the case of this stone and current recommendations, dogs with struvite crystals don’t need to be on urinary S/O long term and is even on the Royal canin website. It comes back to the etiology and type of stone. I do agree some dogs may need to be on a urinary diet long term and it likely won’t harm them but again, if it’s not medically necessary, why continue to give it.