Why do you get one grey hair every few months or so?

Im 24 and i get like one grey hair once in a while, it cant have grown it had to have just appeared! Im sure other people get it too i was just curious why that happens? TY!!Why do you get one grey hair every few months or so?
stress maybeWhy do you get one grey hair every few months or so?
Hair grows white when the color pigment (melanin) ceases to be produced in the hair follicle and small air spaces take its place. Check out http://useinfo-grayhair.blogspot.com/ for more info on gray hair.

best antivirus software