What a time to be alive! Me, I drink when I'm thirsty.
It is also well known that it gets worse with age - fainting due to dehydration is a common occurence with the elderly.
You'll save yourself a lot of future pain.
-Old Zen Tale
https://mobile.nytimes.com/blogs/well/2016/05/09/dehydration...
In most cases, thirst is a reliable signal that more water is needed.
No, as another commenter pointed out, what you've read is bullshit.
"If we prioritise for intelligence then they'll eventually just write a bash script, none of this vague hormone and 'feeling' nonsense."