Do you ever wonder why technical support people always seems to recommend you to try rebooting your computer whenever you report a problem?  Do you think it’s because they don’t know how to fix the problem?  Do you think they are just trying to be annoying?

 It could be a mixture of both, but seriously the real reason a technician will always ask you to try rebooting your computer is because they know that a lot more occurs during a system restart than many people are aware of.  When you reboot a computer it does not simply power itself off and then back on again, though it seems that way.

 When a computer is restarted the operating system performs a series of diagnostic checks and fixes any problems it detects automatically.  If a program was eating up your memory or temporary hard drive space those resources will be freed up following a reboot.  Computers, even those just out of the box have lots of software installed on them, some you will never see or interact with.  The longer software runs the more likely it will begin to misbehave.  Rebooting a computer restores the hardware and software to a refreshed state.TU

 Also, rebooting helps in troubleshooting.  If you reboot and the problem goes away then we know that the computer was just ready for a reboot.  If you reboot and the same problem repeats itself the list of possibilities are narrowed and further troubleshooting can focus on resolving the problem rather than identifying the problem.

 Here are additional tips:

 You do not have to wait until you have a problem to reboot!  Be proactive and reboot nightly or weekly.   Wouldn’t you rather reboot on your terms than be forced to reboot when you are in the middle of typing a paper?

This is not a Windows thing!  Macs and Linux computers will also suffer from resource overload if they are not rebooted regularly.

More info :
Microsoft: Turning Off your computer properly
OS X Mavericks: Schedule a shutdown