I microchip every dog I own and every pup I breed and I require that the owner select the lost and found option on the AKC paperwork. I purchase ISO chips from the AKC at a very reasonable price and if the pup is sold or transferred the Companion Animal Recovery goes with the dog. You pay one time, no annual fees and your dog is permanently identified and scan-able by just about every microchip scanner on the market and is approved for international travel. The CKC issues microchips for every puppy that it registers so that every dog that is registered is permanently identifiable. I used to use a different brand of chip and the annual fees plus people not registering them with the company became an issue and I would receive calls from the company asking me who the dog belonged to.