Every dog needs a collar, chiefly because they need something on which to hang their leash, license, ID and rabies vaccination tag. There are so many styles of collar out there that it's easy to get one that reflects your dog's (or your) personality—but collars serve purposes beyond identification and decoration and not all kinds of collars are appropriate for all, or even any, dogs.Every dog needs a collar, chiefly because they need something on which to hang their leash, license, ID and rabies vaccination tag. There are so many styles of collar out there that it's easy to get one that reflects your dog's (or your) personality—but collars serve purposes beyond identification and decoration and not all kinds of collars are appropriate for all, or even any, dogs.