The last time I was at the hair cutting salon, the person who washed my hair asked me if I washed my hair everyday. I said I did, and she said she could tell. I'm not sure what she meant by this, but please tell me how she could determine this, and what is the best overall practice for washing hair in terms of frequency. I'm interested in the health of my hair as well as the health of my scalp. Thanks for you help!