Arguments for turning your computer off. Wear and tear on your computer, especially items which move or spin (such as the hard drive or fans), is based on the number of hours they are on. If your computer is sitting idle at 4 AM, the fans are still spinning and counting down the hours of usable life they have left. Power usage goes down when a computer is idle, but there is still a large power draw. If your computer is in use for 4 hours a day and idle for 20 hours you could be wasting thousands of watts of power per month. Unattended software updates late at night can be problematic, as you may sit down expecting a working computer only to find something went horribly wrong at 3 AM and you needed to get work done urgently. Which argument is right? In this writer’s opinion, I’d rather save the energy and wear/tear and shut down my computer. Depending on the operating system, you may experience slowdowns and memory problems the longer the computer is on due to memory leaks or files not correctly closed, but most modern operating systems can handle being left on for a long time. Mac based computers are far more reliable, and can be left on weeks at a time in most situations. For a work computer that you leave on all the time you can regularly reboot it once a week to get a fresh start and make sure any updates that require rebooting are performed.

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