NEW YORK ( MainStreet) — Some 70% of employees fail to use all their vacation time, according to a recent Right Management study, and that can prove costly.

"Such a reluctance to take all of one's vacation is a sign of an intense, pressure filled workplace," said Monika Morrow, senior vice president with Right Management. "This is a trend that's grown during the recession and we may in fact have a new norm, which would be unfortunate."

When they do take time off, 37% of Americans take less than a seven-day vacation, according to Good Infographics.

"Vacations are crucial to staying prosperous because you are healthier, less likely to get burned out, more likely to come up with new ideas regarding your business, and it is likely that you will have more authentic relationships," said Kimberly Clouse, advisory board chair at Covestor, a registered investment adviser based in Boston.

Unlike other developed countries, the United States has chosen not to mandate that employers provide vacation time, and the biggest culprits of the all-work, no-play mindset are often supervisors.

"It's the boss who sets the example and sends the message, and if the boss won't take all their vacation time, then workers will pick up on that and may be inclined not to use all theirs," said Morrow.

Those who opt out of their hard-won vacation time risk feeling overworked. Among employees who report feelings of being overworked, 20% say they make a lot of mistakes, 39% report feeling anger towards their employers and 34% resent their co-workers who work less.

"Worst case scenario for workers who don't take vacations is a total mental breakdown," said Patrick Watson, CEO of Hagin Investment Management. "Mental fatigue can also lead to increased drinking, sleeplessness, over eating and even drug use."

Without frequent time off, a job or career can be hard to appreciate.

"If you earn a lot of money but never enjoy it, you're going to be one grumpy rich person," said Noah St. John, author of The Book of Afformations: Discovering the Missing Piece to Abundant Health, Wealth, Love, and Happiness (Hay House 2013). "Taking frequent vacations can remind you of the purpose of making money in the first place, which is to be happy and enjoy life."

When prosperity is a result of creatively solving problems, time off is essential to perpetuating it.

"To become highly prosperous and to stay that way requires facing a lot of complex issues every day," said Watson. "Unless you can take a step back and look at things from a different perspective you can get lost in all of the details and lose the theater wide strategic vision. A vacation is a break from the everyday. It's also a great time to brainstorm and problem solve. The quiet, relaxed mind can be free to be more creative."