Some people just can't be bothered to check them on a regular basis. Same goes for tail/brake lights.
I regularly check the lights on all three cars. The only problem I ever get is in checking the indicators as some clown when asked to help by observing those that need a person in the driving seat (brake lights for example) will tell me that the indicators are working .... No they're not, yes they are, no they're not, yes they are ....... gets tedious after a while.
