Yesterday’s exciting tools become tomorrow’s headaches if we don’t set some ground rules for using them. E-mail, for example, is now one mega-migraine: According to Ferris Research, American white-collar workers spend a quarter of their workday sifting through e-mail. While you can’t really ignore your e-mail, there are guidelines that can help keep it under control.

First, set up your e-mail’s spam filters to block junk mail. Doing so can eliminate as much as 90 percent of your e-mail burden. Then start each day by examining the remaining non-spam e-mails and take one of three steps with each one.

Act. Respond immediately if it will take you less than two minutes to do so or if the message is so earth shattering that it just can’t wait.

Defer. If the message doesn’t require an immediate response, leave it in your inbox and try to answer it by the end of the day.

Delete. Nuke any junk e-mail that your spam filter didn’t catch, or that doesn’t require action.

After you work through the initial batch of e-mails at the beginning of each day, return to your mailbox at least once every two hours and follow the same procedure for five to 10 e-mails each time. This ongoing process of elimination and organization should help you handle your e-mail without going postal.