I know this, yet it is just not practical with as much as I travel. One of my cats has/had pancreatitis, which is likely caused by a dry food I used to give her (Nutro) that I thought was good. From what I've been told this has the potential to develop into diabetes as she gets older; if it does I will probably have to euthanize her. I can't expect to pass that burden off onto another person. She refuses to have anything to do with wet food. I used to have to give her pills once a day and the vet said just mix them in her wet food. Yeah right. I've tried them all, even the ones at more than $1 a can, and she tries to bury them. So she eats dry, and I have to hunt for stuff that fits what the vet told me - greater than 30% protein and less than 10-12% fat. That's harder than you think, when you also try to find cat food that doesn't have corn in the first five ingredients.
The other cat now, she likes and practically demands wet food at this point. So I give it to her, thinking the more of that she eats hopefully the less of the dry food she eats.
I also rub their teeth with toothpaste at least once a week, sometimes twice a week. Even that small amount seems to make a difference, as it's been about 5 years since the older cat had her teeth cleaned and the vet says they still look good. Not great mind you, but they don't need a scaling.