Not only that, but you have to also account for the time that the locksmith spent learning the craft. And the opportunity cost of that learning/practicing time.
This. While common in many fields, I feel that this is most obvious with musicians. "What? I'm not paying this band $1000 for a 2 hour performance!" When, in reality, you are paying them for many hours of practice in order to prepare for that 2 hour performance as well.