Considering the whole goal of television salesmen is to have us return to buy more televisions when the old ones give out, perhaps we shouldn't trust the settings they provide by default. By fiddling a bit with your TV's settings, according to cnet you can:

Increase Your Set's Lifespan: TVs are a lot like bonfires: the brighter they burn, the faster they fade. Turning down your TV's contrast control can greatly increase the life span of the tube, the plasma panel, or the bulb that produces your TV's light.

Reduce Headaches: Ever watch a small bright television in the bedroom with no other lights on? Ever wake up with a headache? The two may be connected, and reducing the brightness of the television can save you money on aspirin.