From my experience with cats I've found that cats tend to nibble throughout the day so I always had a bowl of dry meal out for them. It sounds like your feeding your cats canned. Are they eating it all right away? If not and it's sitting for any length of time there is a good possiblity it can 'go bad'. I don't know that giving your cats canned food is that much worse (health wise) then giving them dry but besides the fact that it can be left out for them to eat when they want, the hard pieces help clean their teeth (just like dog treats for dogs). You can get dry foods that also contain some softer pieces. As for the sam thing everyday? I sure wouldn't want to eat the same thing everyday. Always stay with the same brand (brand changing can upset their digestive systems) but vary the flavor. You might try mixing the two together in the morning (if it's being right away) and just leaving the dry out for the rest of the day. Hope this helps you out.