When we moved to our house two and a half years ago we got our three cats chipped. This came in pretty useful when a year ago we had a pool put in and our Tortoiseshell, Missy, went missing. We think it may have been the construction that freaked her out.
We put up posters but no one responded. Then a short while ago we got a call from a vet. A family had come in with a cat to chip her and had just discovered she belonged to us. It was exactly a year since Missy had disappeared and it turned out she wasn’t far away. It was weird that the people who had her didn’t take her to the vet for all that time. Maybe she wasn’t sick, then caught a cold so they thought ‘Let’s get her chipped’ when they visited the vet. We’ve kept Missy inside for two weeks to make sure she’s safe with us.