Experience and the mallet
Have you heard this one?
A machine breaks, the assembly line is down, the workers are idle, and nobody can fix it. The foreman is despondent thinking of the productivity (and money) being lost!
Finally he called the old guy who had recently retired who agreed to come fix it. When he arrived, the old guy listened to the machine for a few moments, and then suddenly hit the machine with a mallet. Machine fixed; assembly line working again.
The foreman was ecstatic.
The retired mechanic sent the manufacturer a bill for $7500 for getting the line back to full production. However, the playbooking department rejected the bill, demanding to know how he could charge so much for being onsite for only a short time.
So he sent another bill, this one itemized:
hitting the machine with a mallet (one hour): $50.00
knowing where to hit it (a lifetime): $7450.00
Sometimes you need an old guy with experience who knows how things really work.