Last December, I heard that shampoo makes your hair worse by stripping the oil that’s normally produced in it. This causes a variety of hair related issues.
I also heard that soap does the same thing, but to your skin.
Out of curiosity, I tested this out by shampooing half my hair and soaping half my body for a month, while washing the other half only with water.
It turned out that the half with no soap/shampoo actually looked better by the end of the month, with no discernible odor. Some persistent acne also cleared up.
The downside to this is that in the weeks in between, my hair and skin were extra oily before my body seemed to just stop producing all that extra oil. It took about 3 weeks for my body to adjust. Luckily, I had no real social engagements that month, so it worked out.
It is rather freeing to not buy shower products.