I’m a fan of drinking to thirst or just ahead of it. I think people can comfort drink when there’s drink stations every mile in the major city marathons. The reality is if you drink to thirst, it’s better.
Water is fantastic, but to hydrate when performing consider adding things like electrolyte tablets that are going to have more sodium, potassium, magnesium in them, without sugar. It’s going to turn your water into something that the enzymes are more interested in. So the absorption rates are higher and hydration rates are better.
It’s better to drink little and often of those drinks than to drink lots of water, which eventually doesn’t have the right effect, particularly when it’s warmer. And in extreme cases when you drink too much water, it can induce hyponatremia.