The most important lesson that your dog should learn is to come to you when you call him. That, and learning to do their “business” in the backyard.
A dog that can answer your calls enjoys more freedoms than other dogs because he can play in leash-free parks and stay outside by himself, and that’s because the owner knows that once he calls his name, he will be there!
On another hand, the leashes could slip, collars may break, and doors are inadvertently left open. If something happened, one recall could save his life. So this is why it is very important to teach your dog how to respond when he hears his name.