Mother Nature always wants to be balanced. So there's no age where they don't want to return back to normal. I have worked with dogs that are 11 years old, 13 years old, which you witness in the show. I worked with a dog that was 13 years old that was extremely territorial to her food. And I was able to accomplish a calm, submissive state, which is allowing for you to create rules, boundaries and limitations. The mind backs away from the food. So in their world, they are always ready to balance. It's the human who fights it. Cesar Millan