Old school 1980s-era thinking held that turning a computer on and off would put a strain on its components because there might be a power surge when it was turned on. This power surge, it was believed, would cause the computer to wear out prematurely.
With modern computers and modern computer power supplies, this thinking simply is not true. In fact, the opposite is true. Leaving a computer turned on all the time will wear it out prematurely.
Consumer-grade computers (i.e., anything outside of military-grade equipment) are not designed to be left on all the time. With laptop computers, this is especially true. Unless you are using a Panasonic Toughbook or some other ruggedized laptop used by police departments and the military, you should be turning off your laptop, at least at night, when you are through for the day.
Some people complain that it’s just too much trouble to endure the inconvenience of actually having to turn their computer on and then wait countless seconds for it to become ready to use. They want their computer to always be instantly ready to use, so they prefer to simply let their computers “sleep.”
While a properly configured “sleeping” computer can save electricity, even so-called sleep and power-saving modes like standby and hibernate still needlessly waste electricity. Why waste even a little electricity when you don’t have to waste any?
With all that said, one of the most important reasons to turn off your computer on a regular basis is that many security and performance updates and patches will not fully install until the computer has restarted.
I’ve seen many situations where a computer user thought everything was up-to-date, only to discover their new security protections would not actually be there until the computer was restarted.