Don't forget how often we take a bath.
Actually, I was recently reading a great article on Cracked about things in history we get wrong, and that whole "people didn't take baths" is one of them. I guess it spilled over from the Romans who were actually a bit OCD about their hygene, (in a let's all go hang out in the tub kind of way.) Anyway, it was more like colonial times where bathing was the issue. At some point someone got it into their head that taking baths is what was spreading all the germs....
Hmmm... I can't remember. I have to find the article. You'd probably enjoy it. I like Cracked because they break things down into listst (5 reasons of something interesting!) It makes it easier to read for me.