My mom e-mailed me recently posing the commonly heard computer question of "Should I turn it off or leave it on?" I belong to the turn-it-off crowd.
Leaving it the computer does waste electricity, but if the system goes to standby the electricity is not very much. Computer systems are all different but standby power consumption is very little. The good side of leaving it on is the system does not cool down and then warm up again when turned back on.
Some people believe the cycles of on and off creating periods of warm and cool are what makes electronic devices fail over time. The theory is it causes different things to occur like "chip creep" or it causes an "open" condition in a solder joint. Chip creep is terminology that describes how an IC device slowly backs itself out of the socket it's plugged into. For an analogy, think about the AC plug for the TV. If every time the TV was turned on and off the plug would come to a point where the TV would not power on any more because the connection is lost.
All that aside, I turn it off because of the fire hazard potential. Computer power supplies are the component with the highest failure rate. They typically have one or two fans with the cheaper ones usually having only one. The fan performs double duty by cooling the power supply and exhausting the warm air from the computer case. The fans tend to collect dust, dirt, pet hair and whatever else can be drawn in which, in turn, slows down or stops the fan causing the computer to overheat and, worst-case, catch fire.
Turn it off, mom.
Ron Poland is a professor in the Computer Information Systems AAS program at Clinton Community College. Poland is certified in company repair and networking by the Computer Technology Industry Association (CompTIA). He is also a Cisco certified network assistant. Questions may be sent to him via e-mail at firstname.lastname@example.org.