Agreed that a great mechanic can be worth his weight in gold, perhaps even literally over a 40 year career, if he's not too large a person.
Too often they tend to be tempermental, alomost like the caricature of a brilliant chef, but the guy I've had for the past 16 years is not only the most technically proficeint golf course mechanicI have ever seen, but completely unperturbable come what may. He is so good, that he doesn't even play the same music on the shop radio everyday, he has eclectic tastes that run from pop to country to jazz to classical to blues to salsa to flamenco, so it never gets old.
If I were forced to start layig off staff, the mechanic and I would be the mast two men standing.