All of my cats are indoor only, wear collars with tags and are microchipped. Not everyone thinks to have a cat scanned for a chip, so the tags and collars are very helpful in those situations. Their new tags will say "Indoor ONLY". None of them are prone to running out the door or anything like that; but, natural disasters (particularly tornadoes in my area) and emergencies happen and I want to make sure if my cats get out or get displaced, that they are well identified.