1) It is usually done improperly, leading to a cycle of bribery and blackmail. 2) People often use treats as a solution rather than a tool. The last stage of treat training, skipped by the vast majority of practitioners, is weening a dog off of treats; teaching the dog to perform the same actions without the treat as a motivation or reward. Why start?

It has all the problems of treat training, given that it requires treating the dog, and is much harder to do correctly. It can be useful for training service and working dogs, but is unnecessary for most people.

1) By design, they maintain tension on the leash between the human and the dog. This means that every time one is used, the dog is being trained to pull. 2) They are not safe. They offer no means to get you and your dog at a heel position quickly in an emergency. 3) They allow a dog to get further into neighbors’ yards than is legal in many cases, and further than is courteous in any case.

Nothing, I love harnesses. They are my preferred tool for use with dogs that have mastered loose leash walking. Harness are not good tools to use with most untrained dogs, particularly those that pull, lunge, or exhibit other less desirable behaviors on leash.

Yes. It is rare that someone researching dog training has only one problem, or one problem that can be fixed in moments. Diagnosing the problem and developing a curriculum to correct the issue can be immediate. Achieving the desired behavioral modification involves explanation, demonstration, and reinforcement. It generally takes multiple sessions with the dog and their human.

No dog is too old or too young for training. They can always learn new skills and behaviors.