I have often heard it is best not to power down your system at night, any of you IT guys have an opinon on this? I always shut my rig down at night, but it is a new computer and I don't want to damage it by turning it on and off all the time, so what say you?

I've been a computer technician for 20 years, and a network engineer for 12 years. I also worked as an auto mechanic for 10 years prior to getting in to the computer field. Computers and cars have alot in common, for example most mechanical failures in both cars and computers occur during start up. Generally, when someone tells you they've had a failure, you'll often hear, "It was fine last night, but when I started it up today..."

Cost
That being said, I never leave my computer on when I'm not using it. The main reason is it is a huge waste of energy. That 450 watt power supply is no different than a light bulb, so imagine running a 450 watt bulb 24 hours a day.

Computing Unplugged estimates that a typical PC with a large power supply, a good video card, and a few hard drives adds $10-15/month to your power bill when running 24/7.

Also, manufacturing processes have changed and most equipment today is designed to be turned on and off.

Wear and tear
The next thing to consider is the wear and tear on things like drives when running your computer 24 hours a day. Your car is most likely to be damaged when you start the engine, but you wouldn't leave it running 24 hours a day.

That's because the gas costs would be astronomical and leaving it running puts a lot of wear and tear on moving parts like bearings and lubricant. These are generally same type of bearings and lubricant you might find inside your hard drive or the fans in your computer.

Rebooting is good
Another thing to consider is the operating system. Unlike expensive server operating systems, consumer operating systems (like Windows XP) are not meant to run for days or weeks or even months without being restarted.

Many of the write and save operations of modern-day operating systems occur during shutdown. It's important to run your computer through the shut-down process to make sure many of your settings get written to the OS and registry.

Rebooting is good for system updates
How about system updates? As anyone knows that runs a computer nowadays, updates are a way of life. Most people have Automatic Updates turned on for their computer. But did you know that most of those updates don't take effect until you restart your system, even if they don't prompt you to restart?

So if you go for months at a time without a restart, you may as well not even do the updates. The other possible issue is if you have not restarted your system for a month and suddenly you are experiencing a blue-screen or problem on boot-up, you now have to retrace what you have done over the last month to find the culprit. If you shut down every night it is much simpler to find the problem.