I do not leave any food out. Cats aren't cows
, they don't need to graze all day, and having food available all the time is actually hard on their bodies! http://feline-nutrition.org/nutrition/free-feeding-food-cats-are-not-cows is an article about why cats don't need food available all the time.
Also I forgot to add , I kinda feel guilty if i dont put out some dry kibble for them while im at work.. do you let your cats graze on any type of food while your not there?