The biggest factor is diet - a large portion of ingested water comes from food.
Someone who snacks on carrots is going to need to drink a very different amount of water to stay hydrated as someone who eats jerky and crackers.
There’s also obviously differences in kidney function, salt retention, even just body size. Current medical advice is to just drink when you are thirsty, which works for just about everyone.
The biggest factor is diet - a large portion of ingested water comes from food.
Someone who snacks on carrots is going to need to drink a very different amount of water to stay hydrated as someone who eats jerky and crackers.
There’s also obviously differences in kidney function, salt retention, even just body size. Current medical advice is to just drink when you are thirsty, which works for just about everyone.