If it’s recommend that a person drinks ~2 litres of water a day… then how did people go, say, over 100 years ago? I manage to get in around 8 glasses of water a day, but then I’m pretty much always sipping away. I’m thinking that would have been difficult in the days before bottled and/or plumbed water. And even more so further back in time when bathing in a tub was considered an extravagant luxury.
Just a random wondering.