Personally, I never turn my main computer or home server off. This has been an age old debate for years. Really it depends on how much you use it. I use mine probably 18+ hours a day, so I restart it probably once a week, and keep it on the rest.
If you don't use it often you're fine to turn it off. If you're somewhere in between, put it in sleep or hibernate mode.
Most modern Antivirus programs these days offer real-time scanning or you can schedule them to run if a scan was missed. Once a week is what I usually recommend. If you want to make 100% sure scans are complete you can always run them manually.
answered Jan 24 '12 at 09:16
Keep all of your computers turned on for as long as you need them. If you hate slow startups, consider hibernate mode or sleep. And if you're having overheating issues, have the computer cleaned from any dust or replace any old fans.
Machines, unlike humans, don't need a break and can work 24/7. Whether you'll turn the computer off or not is entirely up to you! :)
answered Jul 06 '12 at 01:29