Should I Keep My Computer On, Or Turn It Off When I’m Not Using It?

Posted on: June 5th, 2009

This is a question I’ve been asked many times and it seems like there are numerous views on this. I’m just going to tell what I’ve learned about this.

I found that there are two reasons why people decide to keep their computer on all the time, instead of shutting it down when they are not using it:

It takes too long to get the computer started.
Somehow they got the idea that turning on and off has some kind of damaging effect to the computer.

Let’s see reason #1: A computer should start up and be responsive to user actions in one minute or so. If it takes 2 or more minutes then there are issues that need to be fixed on the computer. Faulty hardware, incorrect settings, viruses, too many start-up items, ineffective antivirus, and so on, can cause a slow start up. These almost always can be fixed and the startup time reduced to an acceptable level. Also there’s a feature in Windows that works on all, but the oldest, machines and allows a significantly faster shutdown and start-up process. It’s called hibernation. I wrote an article about this a long time ago called Saving Time and Energy

Now, reason #2: I actually found no evidence that turning off and on a computer shortens its lifespan. It’s probably one of those myths that keeps going around. In actual fact, computers that are always on tend to fail more frequently. It’s because computers have moving parts in them, such as the fans and the hard drive. The more these run the more chances there are that they fail.

There are also another two factors that weigh against keeping the computer on;

Energy costs. Computers use up electricity all the time when they are on.
Power fluctuations. This could mean too much power, or too little. Most computers are on surge protectors which protect them against most electrical surges (too much electricity). But I very seldom see a computer on a battery backup which is the only thing that would protect a computer against power outages – both blackouts and brownout (partial loss of power). Very short, repeated loss of power is the most damaging to a computer and a surge protector does not give any kind of protection against it. Some parts of town have more frequent outages than others.
One thing that a sudden loss of power can cause is data corruption. If the computer is in middle of writing something to the hard drive and the computer loses power then all kinds of complications could happen and most of the time this manifests itself in the computer not being able to start up.

A computer in standby mode is still running just at a much lower speed and using less power. However, it’s still susceptible to the issues created by sudden loss of power.

Laptops, as long as they have a working battery, are protected against short power outages.

So my answer to the question is:

Shut the computer down (or hibernate it) when you are not using it for half an hour, or more.

I also recommend unplugging the computer during lightning storms and most definitely if you go on a vacation.