R-rated... you mean like Terminator? In childhood (before 6). Nobody where I live at that time was cared or even known of ratings. And so watching them was not prohibited at all for any age. Same for games, many little kids was played MK, with parents knowing that, and don't care. If you mean porn, than at 15. It was on my PC when I bought it, since that PC was build for friend of shop worker. But that friend gone off somewhere and so PC was bought by me. Having many soft, music, some movies, and porn copied on HDD already.