Well, since this thread seems to have drifted into headlight land...

Modern headlight bulbs are much brighter and produce a broader beam than old style "sealed beam" headlights. For that reason, it's not as obvious as it used to be, from the driver's standpoint, that a bulb has burned out. Lose a headlight in a 1966 Chevrolet, and you know it right off. Lose one in a 2005 Toyota and you may not know it until you get stopped by the police. Check 'em frequently.