Genuine thirst?

Ok, so I know all about genuine hunger, but what about genuine thirst? I'm not fasting at the moment, but I am working on listening to my body right now by eating only when hungry and drinking only when thirsty. Even when I do fast I find that I'm not all that "thirsty" and when I am, it's moreso at night only. I know what it feels like to feel thirst, like water is all you can think about until you get it, but it just doesn't seem like enough? Can our thirst mechanisms be off just like hunger? Does just feeling a little "dry" in the mouth count or should I only be drinking when genuinely thirsty?

Thanks in advance!!