I had Bailey micro-chipped last year when I had her spayed. We have moved since so I just called the 1-800 number for Home Again and they updated all the information.
I never received a tag from them but if your dog is wearing a tag with the micro-chip number on it, can't anybody who finds or steals your dog change the information?
I did it for my piece of mind.
Michele & Bailey

plus another one soon.....