LCD screens don't suffer the problem of image burn-in that the old CRT monitors had.

Here is an interesting article suggesting that you not use a screensaver on a newer model laptop or LCD desktop monitor. It's Mac-centric but the details are obviously geared toward any computer with an LCD screen:

http://www.interrupt19.com/2009/01/05/get-rid-of-your-screen-saver/

The once mighty Screen Saver. Every now and then there’s always some computer related technology that refuses to go away, no matter how obsolete and unnecessary it’s become. Like using Windex on your display, running defragging and optimization tools, and calibrating your battery, the Screen Saver is just one of those things that should never be used. Forget what the old timer computer guy says, here’s why you should get rid of that Screen Saver.

What was the Screen Saver for?

The now obsolete screensaver was invented back in the days of CRT monitors. When left alone for a period of time, an unchanged screen would become burned into the monitor. If you walk up to an older ATM machine, you’ll see the “Welcome to … Insert your card” text noticeably burned into the screen.

Screen Savers were invented to turn on after a period of time and change the imaged displayed so that burn-in never occurred. Today’s LCD displays do not suffer from burn-in.

The Screen Saver is bad for your LCD.

It’s not good for your LCD to be on constantly. Like a CFL light bulb, your LCD’s backlight has a certain number of hours before it burns out. Granted, its a huge amount but over the years you have your MacBook, iMac, or Cinema Display, these hours add up.

In addition to your LCD’s lifespan or Mean Time Before Failure, as the LCD display ages it becomes progressively dimmer. Why push your LCD display, which is the most expensive part of a laptop, to an early grave for some beach scenes or a colorful squiggly line?

Screen Savers cause unnecessary power consumption.

The LCD display and it’s backlight account for a large portion of your Mac’s power draw. Yes, it’s much less than a CRT but when a computer is left alone to idle, all that electricity used becomes wasted while your MacBook runs the Screen Saver. Wasted electricity adds unnecessary costs to your workplace, home and the environment.

Modern operating systems contain a feature called Power Management. This means that after a certain amount of time, OS X will shut off the display. After another period of time, OS X will put the Mac to sleep.

Unnecessary power consumption also factors into your MacBook’s battery life. If you conserve the battery, the MacBook will last significantly longer before needing a recharge.

Screen Savers can interrupt and ruin important tasks.

One of the first times I ever experienced this gigantic annoyance was soon after I purchased a new G4 years ago. I was rendering some audio and frankly, back then sometimes things like this took a long time. I walked away from the computer for a while and came back to the screen saver running. I forgot to shut it off and when the screen saver kicked in, the process was ruined - the CPU was busy calculating the screen saver and not my process resulting in stutters, glitches and skips.

This goes for any CPU intensive purpose that takes a long time to complete. Professionals using Final Cut Pro, Logic and Photoshop know that a CPU intensive task often calculated in real-time can be ruined by screen savers.

What you should do instead:

So instead of using dinosaur technology, what you should do is set OS X to shut off the display after a reasonable amount of time. This saves your LCD, electricity and any process you had running when you walked away.

Before we start tweaking settings, OS X’s Power Management has a few quirks of it’s own. First, there are four settings and two different modes. The first three settings are hard coded and can not be changed.

These settings are:

- Better Energy Savings
- Normal
- Better Performance
- Custom

Only Custom can be changed. The two modes are for when the system is running off of a Power Adapter or Battery. iMacs and desktops don’t have the Battery mode.

This is a pain because:

- You can’t have multiple custom settings for different tasks / situations.
- You need Administrative rights to alter the settings.
- The three Apple settings are ridiculous, especially for Battery Mode.

To change your Power Settings:

- Go to System Preferences and choose Energy Saver.
- Click the Padlock in the lower left and enter your password.
- At the top, under Settings for:, choose Power Adapter.
- Under Optimization:, choose Custom.
- Adjust the first slider for when you want the computer to automatically sleep.
- Adjust the second slider for when you want the display to automatically shut off.
- Repeat the adjustments for Battery mode.

Note: The settings you choose are entirely up to you, I go with a longer time before sleep (at least an hour) under the Power Adapter mode than under Battery mode. (20 minutes). I also use the same rationale with the display - 10 minutes for Power Adapter mode and 5 minutes for Battery Mode.

Turning off the Screen Saver:

Now that your Energy Settings are set, let’s get rid of that obsolete screen saver.

- Go to System Preferences and choose Desktop & Screen Saver.
- Click on the Screen Saver tab.
- Slide the slider at the bottom all the way to Never.

The Presentation:

There’s always the situation that drives everyone crazy - the Presentation. If you’ve experienced this before then you know what I am talking about. If you don’t, it’s when you are giving a slideshow, PowerPoint or some other presentation and the screen shuts off in the middle of it because of your Power Settings.

Since Apple doesn’t give you more than one Custom setting, and their own settings don’t include a Presentation setting, use Lighthead Software’s Caffeine. Its an incredible utility to keep your Mac from falling asleep. Just turn it on before your presentation and everything will go smoothly.

I turn off screen savers all the time.

They interfere with maint tasks and such.

Remember having "After Dark" on my first computer. I miss the flying toilets.

Havent used a screensaver in years.  Just set your computer to power off the monitor after 15 minutes or so.

this is exactly what i do.

Me too.

+1, I've never used screensavers, never saw the point versus shutting off the display which is what this article advocates

After dark used to RAPE our old HP.   God I hated that thing.

Also impossible to uninstall.

Oh it got uninstalled during one of the many times i had to wipe the hardrive and reload all of the software.

It was probably the best day of my life up until that time when our monitor caught on fire and dad said "Why don't we just get a new computer."  That was Feb 2002.

I am typing this to on that same computer.

Yes they do. My last 2 LCD's eventually had either the desktop pic burn in or the IE toolbar.

I always thought turning something on and off was just as bad or worse than leaving it on.  Kinda like the CFLs mentioned in the article- they're supposed to last a long time but if you turn them on and off a lot they won't even last as long as incandescent bulbs.