Our Plant's Chief Maintenance Man was on the job for 50 years. Finally, at age 70 he retired. He offered to be a Consultant on Retainer and come in as needed. At that time the Plant Manager was a young guy with an MBA, and he balked at the idea.
Weeks later there was a catastrophe and the whole plant was down because of a major machine failure. We're talking $thousands / hour in losses. The PM called in old Joe, but told him only to tell the new mechanic what to do and then send us a bill. Joe spent a half hour and then put a check mark on a part. The mechanic replaced the part and the plant was back up and running.
The bill came and it was for $500. The PM was livid. He demanded an itemized bill.
The new bill:
One Check Mark...................................................$0.50
Knowing where to put the check mark........$499.50