This is my cat Gulliver - Gulliver is 8.5 years old and lives strictly indoors. He has always been prone to stress induced UTI's (ie: moving to our new house, bringing home a new baby, introducing a new animal to our household), but I have been able to manage his flare ups with his diet. He also has developed a more sensitive stomach in his middle age and tends to regurgitate kibble if fed in large portions or excessively.
Over the past year I have changed his diet from being fed 100% kibble to being fed 50% kibble (his dinner meal) and 50% raw or canned (his breakfast meal). The added moisture has helped him tremendously, and the raw has made a huge difference in litter box cleanup!
Fortunately for me, Gulliver is not a picky eater, so I am able to offer him a wide variety of food options. For his kibble he get's 1/4 cup (broken down into two smaller portions spaced out 15-30min to avoid vomiting) of Acana. I rotate between the Wild Atlantic (mackerel, herring, flounder, etc.) and Appalachian Ranch (beef, pork, lamb, bison, etc.) and top it off with either Primal Pet Foods Bone Broth or warm water. For his raw meal he gets 2 nuggets of Primal. His favorite Primal recipes are the Beef & Salmon, Chicken & Salmon, and Pork.
When introducing him to a raw diet, it took a couple months for him to adjust to the texture and temperature difference. Adding warm water to the cold nuggets really helped, as well as mashing it with a fork to begin. He will now eat his raw straight from the fridge and in nugget form, and he LOVES it!
If I don't have any raw thawed out for him, or forget to bring some more home, he gets 1 large can of wet food for his meal. So far, he hasn't complained about what brand or flavor I've put in his dish. Some of my favorites that I like to buy for him are Weruva, BFF, and Stella & Chewy's.