My Huey calibrator corrects for brightness, and has a little gadget which is supposed to sit in a stand beside my computer to check the room brightness and adjust the monitor for it very regularly. The only problem is that each time it checks, my display flicks for a very brief time. That was annoying, so I didn't leave the auto brightness checker thingy running.
My monitors always run on the lowest brightness setting they have. The reason is, I spend hours a day in front of a monitor on and off and it makes it easy on the eyes, plus it helps my prints match my screen well. Using other peoples monitors, particularly laptop screens drives me bonkers, because most of them are glaringly bright. I'm not sure how people can look at them for more than a few minutes at a time when they are so bright.