The number one rule of responsible consumerism: know more about what you’re buying than the guy selling it to you. But it’s a counterintuitive one. After all, you buy based on someone’s pitch to you, that you need what he’s selling. You get something repaired with the understanding that you don’t have the knowledge to fix a problem yourself. But it’s the number one rule of consumerism for a reason: you just can’t trust the guy taking your money to be honest.