Why It's Recommended to Shut Down Your Computer

This is actually a debatable subject and just how often to shut down your computer depends on your computer as well as your needs.

If you own a laptop computer you know that leaving the power supply plugged in for days at a time will decrease the effectiveness of the battery charging time and overall charge capacity. Also laptops tend to have less ability to properly cool and thus left on longer their internal parts are subject to heat stress. However its important to note that the majority of laptops are purchased for portability and therefore may be turned off and on multiple times a day.

If you own a desktop and you use the Internet often you may have an always on connection which means your more likely to leave your computer on for days at a time. Desktops have more ventilation space, more cooling fans, and are overall better at handling the additional heat of being on all the time. But they are designed for long term use and designers know many users leave these on for long periods of time.

Also desktop computers consume a small but steady flow of electricity. In a research experiment a few years ago; a reputable PC magazine ran tests to see if it was more cost effective to run your computer for days at a time or shut down completely at least once daily. What they discovered was that when turning a desktop back on after being shut down, there was a spike in electrical flow. They calculated that this spike actually cost the user more in terms of power use.

A computer that is off requires more juice to start it up and get all its parts running then a computer that is in essence 'idling' while you are at work or sleeping. They also found that this spike in electricity left the system more vulnerable to hardware failure especially in the areas of power supply fans and chip fans.

Servers and many business computers stay on for months at a time and are protected from most electrical spikes by surge protectors; the parts are being used in relative consistency. Laptops are a different story of course but I have left mine on for a few days at a time.