To Karen, Especially: What's This 5 Year Hair Thing?

I saw a local program on television last weekend and wanted to be sure to post this question. There was a professional hair stylist on the show who insisted that your hair changes every five years naturally. He had been a stylist for many years and his other advice on hair care seemed to be quite good. He really couldn't explain whether the change was extremely subtle or varied every five years.I have never read about this five year hair change. Could you please enlighten?Thanks in advance.Jade21