National Train Your Dog Month Training Tip #14: Old Dogs Can Learn New Tricks Too! Now that your dog has mastered all of his commands and is a responsible adult, make sure to continue with his training to stimulate his mind.
Just because your dog knows how to sit and stay, that doesn't mean that he shouldn't be reminded! If you slack off on your consistency, you can bet your dog will slack off on listening.
Socialization isn't just for puppies. Continue introducing him to new people, places and things! Many owners will thoroughly socialize a puppy, then wonder why the same dog (now years old) doesn't like new people! It's important to teach your dog to associate new people and things with nice experiences - say a tasty treat or playtime with a favorite plush dog toy. Socialization is crucial to building (and keeping) confidence in your dog.
Teach your dog a new trick! Never underestimate his abilities! As an adult, we taught our pup to "army crawl" - one of my favorites if I do say so myself. Just like any other age; consistency, patience and praise are all essential to learning a new command.