A dog identification tag is absolutely necessary to care for the safety and protection of your dog. Dogs love to run and play in the outdoors, and sometimes they play dangerous, or forget to come home. Even if you keep your dog supervised at all time and don't let him go out alone, nonetheless you should still get him a dog identification tag since the chances are, sooner or later he will run out unsupervised.
Dogs are always waiting for the chance to sneak out by themselves so that they can explore and meet other dogs. Sometimes the moment I open the door, my beagle Daisy runs out yipping and yapping into the street. It can take hours to get her to come home again, and sometimes I just have to give up and trust that she will come home by herself this time. She usually does. So what would happen if, God forbid, she were to be hit by a car and injured, or perhaps be picked up by animal control, or get into a fight with another dog. If she didn't have on a dog identification tag, the both me and her would be completely out of luck.
She might be put to sleep with no dog identification tag to tell the humane society that there was someone who loved her just waiting to pick her up.
Dog identification tags come in all sorts of stylish options. There are plain metal ones which look just like dog tags in the army for a sort of stylish plastic look. On the other hand, there are bright pink plastic ones which can be seen for blocks and blocks around for the way that they reflect light and their garish color. Daisy has a large one, a deep metallic green, which is an attractive color, yet reflects enough light that people can see it hanging from her neck. I showed her many tags, but this seemed to be the dog identification tag that she most preferred out of all of them.
I don't just make her wear it when she is going out, but all of the time. In addition to showing people where she belongs in case she is lost or hurt, it has the added advantage of showing them that she is a domestic dog and not dangerous. Although few dog maulings do occur, when they do they are so likely to be sensationalized, that it pays to let people know ahead of time that a strange dog is safe.