Dear Straight Dope:
Two computer experts I know have given me conflicting advice regarding when I should turn my computer off. The first said that I should never turn it off--it should just run all night and day. According to him, leaving the computer on saves the machine components from wear and tear and the amount of energy used to turn it on and off is more than the amount used to keep it running continuously. The second said that I should turn it off if I'm away the machine more than a couple of hours because the amount of electricity is greater than the amount used to keep it running during this time. Also, by running your computer continually, he claims, the components will wear out faster due to the heat generated by the machine. Who's right?
Nobody, really. The reason you’re getting conflicting advice from you computer expert buddies is that there are two schools of thought on the matter, the energy conservationists vs. the equipment conservationists. To a large extent it comes down to personal preference and/or usage. F’rinstance, when I work out of my home and am on my computer between 15 and 18 hours aday, I just leave it on. If I’m going to be at the office most of the day and only use my computer for an hour or two after work, then I go ahead and shut it off. I know people who leave their computers on all the time no matter what, and I know others who turn theirs off if they’re going to be away from the keyboard for more than 15 minutes.
Does the equipment wear out sooner if you turn it on and off frequently? Perhaps, but you’ll probably replace the computer before most components fail. The one exception is the hard drive. Moving parts are the weak link in any system and the most likely to fail prematurely. The question is what causes a hard drive to wear out fastest: continuous operation or frequent warm up/cool down cycles due to being turned on and off. A lot of people think warm up/cool down places the most stress on the HD, but again it depends on personal usage: it’s silly to run the computer all the time if you use it only occasionally. As for the other arguments your buddies used, it doesn’t take a whole lot of power to operate a computer, particularly if you enable the power saving features available on most modern PCs, and the heat generated should be taken care of by your fans. If it’s not, you should take it to your local repair shop and get your fan replaced.
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