But precisely because they're so versatile and convenient, the handheld computing devices (and the cell phones and laptops) can extend our focus on work in very subtle and unexpected ways. They help create a mindset of "just because I can" as an explanation for why we find ourselves working in odd places at odd times.

Let's face it, it's probably unrealistic for us to expect to return to the nine-to-five work week with nothing spilling over into the evening hours or weekends, let alone vacations, as was once the case. The pace of business is too fast, the technology works too well, and the expectations of clients and co-workers are too strong to allow us the luxury of having a thick wall between work and the rest of our lives. But that doesn't mean we can't take a more proactive role in deciding just how and when those two worlds meet, instead of becoming overly tired because of being overly wired.

Gil Gordon heads Gil Gordon Associates at http://www.gilgordon.com in Monmouth Junction, NJ. Since 1982, he has specialized in implementing telecommuting and virtual-office programs for employers and in helping vendors develop products and services for that marketplace. His latest book, TURN IT OFF, at http://www.turnitoff.com, has been receiving rave reviews from the business community.