John Dillinger lived by them. Gatsby could recite them. Michael Corleone had them pinned to his fridge.
Much as we'd love to be the perpetual trend setter, flying in the face of convention and society, the rules of style need to be followed.
Men's style retailer Psyche has looked to define some of these unwritten laws by writing them down. We can't believe we didn't think of it first.
From which buttons you should never do up to the correct position for a tie pin, here's the gentleman's guide to wearing a suit.
(Images: Psyche; Rex)