There is an apocryphal tale that goes something like: A man has a problem with his boiler that continues for months and causes him no end of bother. Finally, an expert comes to see the boiler, and the expert taps the case a few times, tweaks a fitting… and then charges the man a large sum of money. The customer is surprised and exclaims: “But you only did 2 minutes of work!”, to which the expert replies: “You are not just paying me for my time today, but the ten yeas of experience that I have!”