WHICH IS THE BETTER DRY CAT FOOD.. CORE OR INDOOR HEALTH?

Between the two Wellness dry food types that you're considering, CORE is the better option because it is grain-free.

You will find that it doesn't matter what I tell  you, the cat will decide for you.  When I have changed foods I go to the store place both bags on the chart and compare the ingredients.  If they are close in price and make-up I get both and let the cats decide.  I also put my dry food in plastic canisters so I can mix the food to suit their taste

My cats like variety so I'd get both and switch foods every couple of weeks. Or let the cat eat one bag, then when it's time to buy a new brand, switch to the other brand. If my cats could answer this question, their answer would be by me all the brands and switch everyday. I don't actually do that for them but they do have several good quality brands and I switch every week.

If your going to feed wellness(kibble), i would ONLY suggest Wellness CORE. The wet food is a good food and is what i mostly feed. Cats do best with a large amount of moisture in their food. I feed a small amount of a GRAIN free cat food, with a mostly wet diet. Also, your want a pet food where the 1st ingredient is not a meal. Meal means it has been cooked and all of the nutrients cats naturally get from raw food.
best of luck!