If you called me John, almost no one who's played music with me would have a clue who you meant. In my living family, there are two others in my generation with exactly the same name, all musicians, one a guitarist/bassist/Keyboard player and another a gospel songwriter and choirmaster, and all born within a couple of years of each other. We have all been mistakenly hired as one of the others, we all bear a resemblance close enough to be mistaken from photographs. I am the only one who took a stage name. They are, no doubt, grateful.