I only use soap/shampoo when showering 1x/month. I've got longer hair than most women and work outside and my fiancée has never said I smelled (I asked her constantly for the first year). My skin is in the same shape as before doing this routine. The only reason I do it monthly is because I enjoy the feeling of my hair when I use shampoo on it.

We also grow our own loofa, and I'd like to replumb our house for a Grey water system, but I'm unsure about doing it since we'll have mixed kids and I'm unsure about their ability to adhere to my routine or finding biodegradable soaps for their skin/scalp