Fashion is fleeting, but style is forever. Authors want their characters to stand out, and there's various tropes that can be used to make their look distinctive. One such way that says a lot about a character's... well, character... is for them to purposely use an Outdated Outfit in everyday life. Rather than a suit and tie, they'll wear finery from London in the 1850's. Instead of a dress, how about a ceremonial Kimono? Instead of business attire, go to meetings decked out in Renaissance plate armor and helmet. Regional chic from past times works as well: a character wearing cowboy gear is sure to look cool and stand out.