Did you bathe today? If you live in western Europe, the U.S., Canada, or any of the world’s other post-industrial countries, there’s an excellent chance you did. And if you didn’t, you almost certainly did yesterday. You also likely washed your clothes within the past week. A century ago, none of these things would have been so easily assumed. Three centuries ago, the odds would strongly favor a negative answer to these questions (Louis XIV of France, for example, took two baths over the entire course of his life). So what changed?