Sure, checking the BlackBerry and mobile phone every five seconds makes us feel productive. Maybe even über-important.

And we’ve all been in meetings that drag on so long it feels like there aren’t enough toothpicks on earth to keep the eyelids pried open.

But when the boss is talking, don’t fiddle with your gadgets – even if it’s to conduct important business.

It’s just rude and might cost you some career points.

“I would mind,” said Tom Borghesi, a vice president of consulting services for Robert Half Management Resources, which recently queried executives on the growing practice of checking e-mail during business meetings. “It might be becoming commonplace, but I frown on it.”

Common doesn’t add up to acceptable, he said.

The specialized staffing firm recently received 150 responses from senior executives about their take on the trend. Eighty-six percent said people they work with often check and respond to e-mail during meetings, and 31 percent said that the practice is “never OK.”

“It’s all about proper etiquette,” Borghesi said. “There are times it might be critical to respond to someone right away. But as a rule, when it comes to e-mail during meetings, less is better, if at all.”

If you know closing a deal or responding to a client can’t wait, he said, let the meeting organizer know in advance that you might have to step out for a moment or two. Twenty-three percent of senior executives agreed, saying it’s OK to briefly leave the meeting to respond to a pressing communique.

But most e-mails can wait.

“The BlackBerry and 24/7 e-mails have gotten us to the point where we think everything is so critical,” Borghesi said, “and it’s not.”

Executives understand e-mail increasingly consumes “such a large volume of our day,” Borghesi said. They might, however, be less tuned in to how they contribute to the problem by running meetings that stray off topic.

“Make sure the meeting is pertinent to the people attending,” he said. “Make sure it’s to the point, and start and stop on time so the perception is you’re not wasting anyone’s time.”

When asked about what might prompt him to interrupt a staff meeting to respond to a pressing matter, Borghesi paused for about half a second, then said, “if my boss wants me on the phone and I’m in a meeting with my team, then I’m going to excuse myself from the meeting.”