I was staying at home alone when I was ten. Both my parents had jobs and I took care of my younger borther and sister (8 and 6 at the time)...ten was a bit young but by the time I was twelve I was more then ready to be home alone, same with my younger siblings. I don't think twelve in an unreasonabe age, I guess it depends on the kid though and the area that you live.But I don't see it as inapropriate or kids who are in need of a sitter.