How do you know what's right for your office wardrobe?

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Three-piece, pin-striped suit. White button-down shirt. Diagonally striped cravat. Wing-tipped shoes. Such was the strict dress code of anybody who worked for IBM in the 1960s. Peek into any IBM headquarters nowadays, however, and you're more likely to see polo shirts and khaki pants.

Across much of the western world, corporations, politicians and even royalty seem to be relaxing their standards for proper attire. Hours after being sworn in, President Barack Obama was holding jacket-less meetings in the Oval Office. Even Buckingham Palace is letting its hair down. Jeans and flip-flops are now accepted apparel at garden parties hosted by Queen Elizabeth. Dressing down, it seems, is positively de rigueur.

Yet, even in this age of running shoes and unbuttoned collars, professional dress codes remain an important part of the modern workplace. For anybody who had to endure uniforms in high school, an official dress code may seem like an outdated corporate relic. But a dress code isn't just arbitrary sets of rules; it's seen as a meaningful component of a well-run company.

Many business schools now require their senior-level students to show up to class clad in suit and tie. Keeping up a closet of well-pressed suits is a tricky prospect for cash-strapped university students, but instructors will insist that it's essential training for the pinstripes and power suits of the corporate world. Clothes make the man or woman, and wherever your workplace may be, you've got to be prepared to dress the part.

Keep reading to find out why techies don't wear ties.