Should You Shut the Computer Down?: "I should mention where I stand on the power vs. stress angle. It's better for the health of your system to just leave it on. The power consumed is, at worst, comparable to leaving a light bulb on, especially with modern Energy Star components, disks that spin down, monitors that shut themselves off, and operating systems that know how to manage power, even on desktop systems. (Incidentally, light bulbs will also live longer if you leave them on, not that I advocate gratuitous waste of energy.) Running away from a problem usually is not a good solution to the problem, and turning off your computer to avoid Internet attacks is the worst kind of running away. It's not even effective. "