Hydration is good. If you hydrate a LOT, remember to have some electrolytes in there somewhere. You don’t need a lot, but some.

Also, the “eight glasses of water per day” thing was made up whole cloth. It is not medically nor scientifically a thing. The best advise is: Drink when you are thirsty. Unless there’s something wrong, that’s your body’s way of telling you it needs hydration.

That said, if you exercise or get your body’s signals confused, thirst might not work perfectly for you. Generally, if you’re exercising, bored, hungry - having a glass of water might be just the thing and usually doesn’t hurt anything, so give it a go.