Does turning fluorescent lights off use more energy than leaving them on?

From an article by John Matson in the Scientific American:

So you bought a compact fluorescent lightbulb in a bid to be green. Such bulbs are vastly more energy-efficient than traditional incandescents and screw into standard sockets. Should you treat them like their older cousins?

After all, four- and eight-foot- (1.2- and 2.4-meter-) long tubular bulbs common in more institutional settings are sometimes left on permanently, perhaps due to their slow, flickering start-ups. The thinking is that the boost of energy such bulbs require to power up means that it might be best to keep them on when leaving a room, rather than subjecting them to the stress of a restart on your return.

Turns out, however, that power surge is so brief that its energy draw doesn't amount to much: the equivalent of a few seconds or so of normal operation, according to U.S. Department of Energy estimates. In other words, from a strict energy-conservation standpoint, it's almost always beneficial to shut off fluorescents when leaving the room—the start-up energy is offset by the power saved in even the briefest outages.

But what about the wear and tear on the bulb itself? Being too switch-happy reduces the operating life of the lamp, and given that newer fluorescents are still a few times more expensive than old-fashioned incandescents, it makes sense to forestall burnouts. There are also real environmental impacts of their production and disposal to consider.

A simple rule of thumb that balances both concerns is to shut off fluorescents if you’re planning to leave a room for more than five minutes, according to Francis Rubinstein, a staff scientist in the Building Technologies Department at Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division. Mary Beth Gotti, manager of the GE Lighting & Electrical Institute in Cleveland, agrees. For all practical purposes, "it almost always makes sense to turn the lights off," Gotti says. "From an environmental standpoint, the best way to save energy is to turn off the things that you're not using."