BOSTON (CBS) – The new uniform at work is jeans. This isn’t a story about construction sites. It’s one about professional offices.

And this isn’t a story about what people are wearing on Friday, but every day of the week.

Sarah Borelli is one of those workers who swears by jeans. “We are at the point where jeans are normal at the workplace. It is definitely around here. We wear jeans every single day.”

That’s the case in more and more offices, regardless of the worker’s gender. In a world in which only 6% of men now wear a tie to work every day, attitudes are definitely changing.

Borelli added, “I don’t need to dress up every day to feel confident in what I do, I am already confident in my job.”

There are four rules every professional should follow to wear jeans successfully on the job.

First, buy a dark wash or black says Steve Simon, president of the National Jean Company.

Simon added that a professional look is just one of the benefits of a darker jean. “A rule of thumb for everybody, both male and female, the darker the jean, the more slender you look.”

The next rule involves fit. Since denim stretches, new jeans should be snug. “It should feel a little tight and you should feel a little discomfort up top, around the top of your legs and waist,” said Simon.

Rule number three is to avoid anything ripped. “Not for the workplace,” according to Simon.

Finally, buy quality jeans made with a thicker fabric. Simon said to consider them a long term investment in your wardrobe. “We have jeans that are up to $280-$300.”

And shoppers are buying them. Sales of jeans that exceed $100 a pair were up 50% for both men and women last year.