The weather seems to have taken an early turn toward autumn in the Northeast, though the calendar only says August. Still, it's vacation time somewhere, at least in theory.

New Yorkers head for the country or the beach. Washingtonians scamper past the Beltway. And the publishing industry all but shuts down. Of course, President Obama is on vacation and Congress won't be back in the capital until September 9.

If you're reading this column, chances are that you're not on vacation. And if you haven't taken a real vacation in a year or so, that's not a good thing--and not for the reasons you think.

Why You Shouldn't Be Reading This

I'm not going to lecture you on the importance of taking vacations. Inc. has already explained why it's important to get away from the office and you're old enough to make your own decisions. Instead, I want to convey that it's important to check out because of the message not doing so sends to your colleagues.

When you skip out on skipping out, you send a signal of disapproval to the people who do. This is especially holds true if you're a leader. Here's why. 

A few years ago, I did a lot of reporting on the U.S. military. One of the things that surprised me at first was when I tried to interview high-ranking officers in Iraq or Afghanistan and was asked to reschedule the interviews around their mid-term leave (mil-speak for "vacation").

A vacation in the middle of a war? Though I understood--and fully supported--this idea, these top-ranking generals, who jobs were particularly challenging, weren't involved any real combat.

I brought this up as tactfully as I could, but the response was that if generals didn't take leave, then the colonels who worked for them wouldn't either. This despite a policy requiring soldiers to take mid-tour leave!

But the buck didn't stop there. If those colonels didn't take leave, then a lot of the best majors and captains and sergeants wouldn't either. And if those majors and captains and sergeants didn't take leave ... well, you get the idea. Neither would the lieutenants and lower enlisted ranks who routinely went out on patrols and saw actual combat.

Your Best People Need Breaks

Here's the thing: Decisions affect other people, and the benefits of vacationing--the psychological benefits and the productivity benefits are pretty well-known. Still, only 30 percent of American workers take all the vacation time they've earned. On top of that, they earn far less vacation time than their peers in other countries.

I understand that the people who most need vacations are sometimes the ones who have the hardest time taking them. If you were running a small start-up and just beginning to see traction, for example, it would be hard to just up and go to the Caribbean.

But if you want the people on your team to take time off--and you should--you've got to lead by example.