Well, prescription vet diets for stuff like this are proven to work, and I've not heard yet of other diets that are not. So with feeding non-prescription diets you run the risk that the crystals may get worse...
Diet is important either way, but were we talking about a boy kitty, its life or death, as they have narrower urethra that can actually completely block up.
That strategy is what I choose for Oscar. I don't even think he has food allergies, but it's a case of me knowing its highly unlikely the vet diet he eats will make him worse, can't hurt, and might even help a little with his allergies.
In the end, its your choice
Honestly, the way I have always looked at it is that although the food is a little more expensive, I do not have the money to be clearing up a skin infection that might come from eating something he's allergic to. ($110 a pop per vet visit and antibiotics, plus possible other products)
I can only please one person per day. Today is not your day, tomorrow doesn't look good either.
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"You didn't know of the magical powers of the break stick? It's up there with genies and Harry Potter as far as magic levels go." SisMorphine 01/07/07