I get hundreds of emails in a day - I can't imagine being able to work without email and it's a quick, easy and cheap way to send and receive information.

In saying that, I still receive many letters - not from adoring fans - mostly client assessments from the Inland Revenue Department.

One morning recently, I received an email from a Government department. I read the email then, as you do, opened the attached file.

Scrolling through the spreadsheet, I figured the attachment wasn't meant to be there. I closed it and felt a moral duty to delete the attachment: it was a database of conference attendees I was not meant to have seen.

I was the only recipient, and to me the data didn't appear interesting. But what if the data was interesting to someone else?

We've seen cases of the wrong email getting sent to the wrong person. Out of the 175 billion emails sent daily there will be human errors, which highlights the importance of having checks in place before you press the send button

Email can also have a cost that's not just measured in social reputation or bad press.

A 2005 study concluded that overdoing email while working could be as detrimental to your IQ as smoking marijuana.

What is thought to be a sign of efficiency by some can be taken as rudeness if you're emailing someone while talking face to face, or on the phone to someone else.

Twenty per cent of emails are copied to others unnecessarily; 13 per cent are irrelevant or untargeted; and less than half, 41 per cent, are for information purposes. Using some of these statistics, a couple of online calculators told me I was spending up to 82 minutes a week, or nine days a year, too long on my business emails.

The same figures stretched over a business of eight employees mean you could lose 72 productive days a year. Based on New Zealand's average hourly wage of $27 that's a labour cost of $14,580.

So to keep focused on high-value productivity, you might want to make changes around email use in your business. Some tips include: schedule times for email use; use social enterprise software for internal communications and email only for external contact; set parameters on who can send external emails; turn away from the screen when you're on the phone.

Or you could just say no for a while and get out for a walk, to clear your head rather than your inbox.