I pieced together this article together from several sources......

Is it better to turn my computer off when I am not using it or leave it on all the time?

This is one of those questions where there is no single right answer. In other words, it depends on how you use your computer.

There are at least three situations that force you to leave your computer on 24 hours a day:

1. You are on a network, and the network administrators back up files and/or upgrade software over the network at night. If that is the case, and you want your machine backed up or upgraded, then you need to leave it on all the time.

2. You are using your machine as some sort of server. For example, HowStuffWorks has a machine that creates the images for the How Webcams Work article. It needs to be on 24 hours a day. If your machine acts as a file server, print server, Web server, etc., on a LAN (local area network) or the Internet, then you need to leave it on all the time.

3. If you are running something like SETI@home and you want to produce as many result sets as possible, you need to leave your machine on all the time.

If you do not fall into any of these categories, then you have a choice about whether or not to leave your machine on.


Some reasons why you might want to turn your pc off.
1. One reason is economic. A typical PC consumes something like 300 watts. Let's assume that you use your PC for four hours every day, so the other 20 hours it is on would be wasted energy. If electricity costs 10 cents per kilowatt-hour in your area, then that 20 hours represents 60 cents a day. Sixty cents a day adds up to $219 per year. It's possible to use the energy-saving features build into modern machines and cut that figure in half. For example, you can have the monitor and hard disk power down automatically when not in use. You'll still be wasting $100 per year.

2. Another reason is component wearout....The opposite factor to thermal stress is wearout. While leaving the PC on all the time reduces thermal stress and hence prolongs system life, it also causes components to wear out more quickly. Left running, the electronics are exposed to heat which over time breaks them down, most components are only rated for so many hours of operation so shutting down when not in use extends the life of your hardware, saving you money and time. This is more of a factor for some components than others--especially monitors.

3. Dust is another good reason to shut down when not in use. Computers are quite possibly the best lint collectors created by man, if you leave it running all the time it will do a great job of filtering your air but you wind up cleaning it much more often, if not, the lint builds up fast and components fail due to overheating or just mechanical failure such as a cooling fan wearing out, bad news on a CPU. Dust accumulates over time. If you smoke around a computer, in a matter of weeks the fans will get caked with crap. If not, dust and debris will still build up on the components and the fans of the machine. Dust reduces air flow, and adds weight to the fans, which can burn out the motors. Obviously, when you leave the computer on the fans continue to run, and so they continually suck dust into themselves, making them cake up faster. If the fans slow down, the hardware components won't be properly cooled.

Combine these two factors: Heat + Dirty fans, and you're looking at a very serious potential problem. If you live in a high dust area, or smoke, or have pets, or just an unclean house/room, the problem can get worse.


The argument for leaving your computer on all the time is that turning it on and off somehow stresses the computer's components. For example, when the CPU chip is running, it can get quite hot, and when you turn the machine off it cools back down. The expansion and contraction from the heat probably has some effect on the solder joints holding the chip in place, and on the micro-fine details on the chip itself. But here are three ways to look at that:

If it were a significant problem, then machines would be failing all the time. In fact, hardware is very reliable (software is a whole different story, and there is a lot to be said for rebooting every day).
I don't know a single person who leaves the TV on 24 hours a day. TVs contain many of the same components that computers do. TVs certainly have no problems being cycled on and off.
Most vendors will sell you a three-year full-replacement warrantee for about $150. If you are worried about it, spend some of the money you are saving by turning your machine off and buy a service contract. Over three years, you come out way ahead!
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What do I do?....I turn my pc off when not in use for longer than about 6 hours. If I do leave it on for a while, like if I'm cleaning the house, I turn the monitor off.

Ultimately, the decision is yours. Hopefully I've given you some useful info to help you decide which is best for you.