If you're looking for a good men's suit, expect to spend a minimum of $400, "unless you find a great sale," says Rachel Weingarten, author of "Career and Corporate Cool." She recommends buying one or two new suits a year and finding a good tailor who can update their style periodically to save money.

"If you made the investment and bought a really good suit, maybe next season the tailor can cuff it for you or change the buttons," Weingarten says.

For women in the office, Weingarten says to steer away from matching suits.

"I see so many professional women wearing pants that are maybe a little too tight because they bought them as part of a suit," she says. "I would say invest in separates that you are going to get more use out of."