Just that, really. I'm a once-a-week person when I don't exercise. I have long hair and brush it multiple times a day. Also we are a non-smoking household and we tend to eat healthily so no smell of frying in the house. I get it that your scalp can smell but anyone I told I can go a week without washing my hair was surprised because it's always shiny and doesn't smell or look greasy (I have dry hair and skin so that may help).
I know some people have to wash their hair daily but that's usually (not always) because they have oily scalps. So I'm curious. How often do you wash your hair?