This is one of the most popular questions we get here at Help2Go. Whether it is your PC at home, or a whole office-full of computers, this has been a question that has plagued many. We have researched this question thoroughly, and the simple answer is that there IS NO simple answer.

However, based on the following criteria, we can help you formulate an answer that will work for you.

Reasons to Turn it Off

Waste of Electricity
Leaving a computer on overnight may not use a lot of electricity, especially if your computer and monitor support the "Energy Saver" features that are standard on most new computers. But make no mistake: over the course of months and years, quite a lot of electricity is wasted. If you are a homeowner or you manage a small business on a budget, this is no small concern. Turn it off.

Security: Internet
If your computer accesses the Internet through a modem, this section does not apply. However, if you use DSL, a cable modem, or have "always-on" Internet access at work, your computer may be an open target for a hacker. If your computer is on the Internet even when you aren't sitting at it, turn it off.

Security: Network
If you work in a networked office, leaving your computer on may not be a bad thing, but leaving your computer on while you are stilled logged in to your company's network is a VERY BAD thing. Make sure you log out every night. My wife's office had an instance of one of the cleaning staff ordering merchandise online using the identities of the staff. You never know who's going to be in your office after-hours!

Windows needs a break
Microsoft Windows is a terribly-written product. The longer you keep it running, the more likely it is to crash and lose your data. If you are a Windows user, then you should periodically reboot your computer anyway, so that the internal memory (RAM) is cleared and Windows starts up with a fresh clean slate. So for stability's sake, turn it off.

Reasons to Leave it On

Running Services
Sometimes, your computer performs a function even when you are not sitting at it. Perhaps it acts as your fax machine. Maybe you use it as a web server. Maybe your company uses it as a print server or file server. In these cases, in order to keep those services running, leave your computer on.

Hardware Durability
It is a fact that turning an electrical appliance on puts more stress on that appliance than keeping it running for a long time. The reason is that the initial surge of electricity through the circuits is a traumatic event (shocking, even). Your computer is an electrical appliance, and therefore constant power ups and power downs can wear out the parts before their time. If the durability of your hardware is an issue, then leave it on.

Convenience
Starting up Windows is a hassle. Sometimes you just want to sit down at your computer and be able to work without having to boot it up and wait for a few minutes. This is a perfectly legitimate desire! If being able to use your computer instantly is important to you, leave it on.

The Big Myth

People will try to tell you that leaving your computer on will open you up to power surges and electrical disasters that will "fry" your computer. This is true, but your computer is susceptible to power surges even if it is off! A power surge travels over electrical wires, and surges don't care if the appliance is on or off. Therefore, if you want to be careful, you should purchase a good surge protector or UPS (uninterruptable power source). Or, for the paranoid, you should unplug your computer altogether when it is not in use.

Conclusion

Look through the above categories and choose which are most important to you.

What do I do? Well, I currently live in an apartment building that pays for all my utilities. Therefore, wasting electricity is not a big concern for me. My computers are connected to the Internet constantly, but are protected by a firewall, so security is not a concern either. Plus, I make sure that I reboot my computer every few days so that Windows can start with a clean slate.

In addition, I like the convenience of having my PC on whenever I need it. The hardware durability is an added plus. So, I leave my PC on all day, every day.

With that said, I must inform you that I am moving into a new house next month. Suddenly, the electricity bills will become my foremost concern, and you can bet your bottom dollar that all my PCs will be turned off every night (except for my web server). House payments are not cheap!