There are many reasons why people would like to keep their PCs running constantly, the main reason being that it is fast and convenient to resume your work. Apple computers are running maintenance scripts that wait for the wee hours of the morning to run. On those machines, if the computer was off, the maintenance script did not run.

New Apple computers run the Snow Leopard (OSX 10.6) operating system, which checks if the computer’s maintenance scripts ran, and runs them at startup if they didn’t.

Windows PCs have traditionally had compelling reasons to be left up and running. Older PCs took an inordinately long time to boot, so leaving them running was more convenient. Heat expansion allowed components to creep out of their sockets over time, but all components are now soldered, bolted, belted, clipped and held firmly in place.

There are now good reasons to turn PCs off when not in use. A PC that is not running in normal mode or sleep mode is not consuming power. PCs that are left running which blank their screens and stop their hard drives from spinning are still consuming power and generating heat. My sister placed a closed laptop in her neoprene carrying case for a cross-country flight and found her keyboard gently melted when she opened the laptop at her destination. The neoprene-rubber case was an excelent insulator that trapped the laptop’s heat.

Another good reason to turn off an unused PC is dirty power and intermitent power outages, surges, and brownouts. In the greater Washington, DC area, we experience electrical power drains that lower the standard voltage (brownouts) and can cause the lights to flicker (outage) and these are all detrimental to PC chips, and can shorten their life.