[hammock]

Thus is the power of relationships, which often goes undervalued in quantitative analysis. For a one-off job, you could pick the most skilled person in whatever trade to do it for you, with unlimited budget $X, and still be unhappy with the results. Because there is no relationship.

Whereas, if you pick someone who your friend uses regularly, by comparison, your job is no longer work $X to the tradesman but the sum total of $X plus ALL the future business from your friend, who will leave if the tradesman does you wrong.