Xavier & our cat, Holly are both micro chipped. Our rescue, Sasha however isn't. We've opted not to with Sasha just because she is 14 and we don't want to do anything to risk compromising her health. Xavier was chipped when he was neutered and Holly was before we even got her. I don't regret it at all! In fact, HomeAgain is wonderful! X has gotten into a few things and I've been so grateful to be able to call their 24/7 number and get advice