I have Ti PB (550 mhz/20 GB/1 GB Memory) and Al PB (1.5 mhz/80 GB/1.5 GB Memory) and 2 more Wintel Laptops. I set up the screen brightness at 15% or 25% ranges on the display brightness setting. I am guessing reduced brightness setting (less stress on the LCD backlight) will prolong the LCD life span. I heard the normal LCD lasts like 60,000 hours (if you use your machines like 5 hours a day, it should last 30 + years, by this estimate). So, if you reduce the brightness at 10% or 20% setting, does it prolong the screen lifespan proportinally? I know LCD itself does not wear out. Only backlight will wear out eventually. I baby my PBs.