The back door is left open and your puppy is gone. Or your older dog wanders away and is unable to make its way home because of diminishing senses. Or your indoor/outdoor cat fails to return at the usual time.
Rather than having your pet considered a stray with the potential of being "put down," the doctor can implant a microchip under your pet's skin.
As painless as a vaccination, a microchip contains pertinent information that can be read by a special scanner to quickly identify your pet as "owned."