The client, perhaps a bit flabbergasted about how much the trainer was charging, said something along the lines of "I can't believe I had to hire someone to help me with my dog." Either that, or the client had asked a friend who had successfully trained his dog to help and the guy couldn't handle the dog.
The trainer's response stuck with me.
Trainer: Can you come by this weekend to take a look at my water heater? It's broken.
Dog Owner: Why would I do that? I'm not a plumber.
Trainer: Exactly.
He then went on to explain to me:
I am a professional. I am an expert. My area of expertise is training a dog. Why would you ask a friend who is not an expert to do an expert's job? I wouldn't ask somebody who, what is it you do? (I'm a writer) Yeah, I wouldn't ask you to come take a look at my pipes if they backed up. That's not your expertise. So why would you have someone who is not an expert come do something they don't know how to do? If my pipes break, I call a plumber. And I pay that plumber for his skill, his knowledge. Yeah, I'm not the cheapest trainer out there. But I've been doing this for a long time, and that acquired knowledge and experience of dealing with these dogs is what you pay for.
I am going to use that explanation for the rest of my life.