Well ofcourse there's a major difference between lights on/off, but is the difference really so big when we're talking about min. vs. max. brightness, especially when idling?

'Cause if i watch movies for approx. four hours straight, and the display is, ofcourse, on all that time, and in four hours, the difference between min. and max. brighness is only ~15min. is it really worth it to suffer with the lowest possible brightness level, when you can use the brightest one and lose just 15mins in four hours (with would theoretically mean that if you keep the display on for 24 hours, you would lose 1,5 hours on maximum brightness).