Not that this is for every cat, but this is what I feed them etc:

1. Origen dry - high protein, keeps the urine pH at a point that inhibits crystals. Just over 1/2 c a day each, in three servings. The first serving is a light crunchy base for the soft food goop (see below).

2. Medical SO (urinary tract formula). 1/8 of a can, soaked in a bowl of hot water, drained and split between the two of them, with 1/2 tsp of salmon oil mushed in. I got it at a pet store. Less stinky formula - and the boys love it!

3. Treats - MediCal, Greenies or non-grain/organic treats. (no 'fast food' treats like Temptations, etc)

Must be doing something right - so far, the vet bills have been for maintenance.