But how do you get the cut?
Mad Men are never baggy. There's a whole list of rules for getting the right fit, but first off it's worth noting that most men buy their suits and shirts too big. Bear it in mind next time you're trying one on.
After that, remember that vertical lines across the shoulders at the back mean the jacket is too big for a classic look, says Gilfillan, while horizontal lines tell you that it's too small.
"There should be an inch of shirt collar showing above the jacket collar at the back," she adds. "With your arms at your sides, your knuckles should be even with the bottom of your jacket."