Do not use screen savers - all computer monitors should go into power-saving mode.
In the past, screensavers were used to prevent "image burn-in", a problem that occurred with older monitors when an image was left on the screen for too long. Modern monitor technology has rendered this issue almost entirely moot, and screensavers are no longer necessary. In fact, the best way to save your screen is to turn it off. Running screensavers requires the use of computer processing power and memory, and as a result uses energy.
Learn how to set your computer to power-save mode by clicking here.