I have talked to a fella at work who has been shaving his down to the skin for years now (he is 36), and he says it is tough for him to grow hair again after all the years of skinning it. He has quite a rough caloused head now due to all the sun exposure from surfing etc.. That is the one reason I don't take it that far with the shave down, I'll save the save for my later years when it won't matter so much. It may vary from person to person as well as far as your hair managing to come back.