I stopped using soap a year ago. It was easily one of the best moves I've ever made in my entire flippin' life.
About this time last year I read an article (which Mark mentioned here as well) extolling the virtues of a soap-free bathing experience. TL;DR version: Your body is designed to regulate itself. Smearing chemicals all over it wrecks its own built-in processes, and screws with naturally balanced pH levels. This made sense to me and I thought I'd give it a shot for a month.
At the beginning of February 2010, I blogged about the results I'd seen so far. I didn't stink at all (confirmed by friends, family and random people I ended up sitting next to on various forms of public transit), my skin felt better, oily and dry patches had all but disappeared and the light dandruff I'd had my entire life was almost gone. I was pleased with the results of my month experiment and decided I'd run with it for a while longer. As of January 1, 2011: it's been a year now, and I can't imagine ever going back.
More on the results I've seen: As I just mentioned, my skin feels better than ever before. Not that it ever felt bad, really, but it feels awesome now. Still no stink at all, I swear even when I'm really active and sweating I don't notice any B.O., and I used to be über self-conscious about this and would think I was stinking if I walked up a flight of stairs too quickly. So this is a huge improvement for sure. And with the exception of changing climates drastically, even the dandruff is history. My previously wavy and mostly unmanageable hair now seems much more willing to bend to my will, a dream of mine since I first looked in a mirror, brush in hand, then tried and failed to make any sense of that monster. So I approve for sure.
And speaking of hair, that was actually a perfect test. Sometime mid-summer I stopped by a barber and before I'd realized it he'd squirted a glob of shampoo onto my head. It was too late to protest, so I just sat through the scrubbing. For the following 2 weeks my hair was a mess: full of dandruff and totally uncontrollable. Once things balanced back out to the previously established no-soap norms, all was good again.
Unexpected bonus: travel is much easier. Now that I'm not lugging shampoo and conditioner with me on the road, there's that much less for TSA to hassle me about and more room in my luggage (which I quickly filled with coffee stuff, natch). Not that I always carried lots of liquid toiletries with me, but now I don't even have to think about what the hotel I'm going to might provide, or worry about having to borrow something from a friend until I can get to a store and buy my own stuff. Those details are gone. I love it.
The future? I will definitely be sticking with this. I'm still annoyed it took me 35 years to learn what I clearly already knew as a baby kicking and screaming when my parents tried to wash my hair. At least that's what I want to assume I knew back then. I know now, but I'd still rather not think about how much I spent on soap and shampoo and related products over the years when they were likely causing all the problems I was trying to protect against.
If you don't believe me, you can totally smell me when you see me in public. Really. Just ask. It won't be weird at all. Okay, maybe a little bit.