Do I need to use a screen saver if I have an LCD screen?

Old "CRT" monitors (the ones based on big glass picture tubes that look like old TVs) were subject to something called "burn in". If a picture was displayed on the screen for too long a ghost of that image would become permanently burned into the screen itself. You could turn the monitor completely off, and still see a vague, faint image that matched what was displayed on the screen. You used to see this on cash registers, ATM machines or other single-purpose devices where the screen typically had exactly one unchanging image on it 99% of the time.

Thus "screen savers" were born. These programs would fire up after some period of inactivity when presumably no one was using the display. They would remove that image that was displayed 99% of the time and replace it, typically with other images, or in the case of desktop computers, animations like flying toasters, pipes or lately even fish-tank simulations.

With an always-changing image on the screen, burn-in was significantly reduced or eliminated.

LCDs naturally use a different technology for display - they don't have the glass surface on which the image can be unintentionally burned into. But that doesn't mean that they aren't susceptible to something similar. Now, I'll be totally honest here and say that, quite frankly, I don't know just how serious a burn-in problem exists with LCD screens (I suspect a more knowledgeable reader or two will chime in, in the comments). What I can tell you is that I have seen ghosting on my LCD screens when I move a window that's been in one place too long. Is that a permanent problem? I'm not sure. It could also easily be attributed to the quality of my monitors, perhaps. But I see it.

So it leads me to this position: screen savers don't hurt, and if there is risk - no matter how small - then they can help.

So, yes, I do recommend running a screen saver, regardless of your monitor type.

But wait, as they say, there's more!

• Particularly if you're in an environment where people can walk by while you're away from your computer, you need to make sure to enable the option that requires a password to get out of the screen saver. That way people can't easily access your computer while you're not around.

• I prefer the "blank" screen saver. Unless there's some reason you specifically want to see something, just have the monitor go black. It saves a tiny bit of power, it doesn't visually distract if you happen to be around but not using the computer, and it doesn't advertise the fact that your computer is running if you're not around.

• Speaking of power, make sure to select the power options now available on many systems that will actually turn the monitor off if you're away long enough. This option actually removes power from most of the display circuitry in the device completely, which reduces power consumption dramatically. The net effect is a blank screen, of course. And it behaves much like a screen saver when you return, except that it might take a few additional seconds to warm up and return to a fully "on" condition.

Yes, I know, I like fish tanks and flying toasters as much as the next guy, but in all honesty, I think that a little energy saving is perhaps a slightly more important priority.

But ultimately, yes, use a screen saver. There's almost no reason not to.