Thirsty? you are already dehydrated
Remember, thirst isn't a good predictor of your hydration status.
It takes about TWO HOURS for anything you drink to have an effect on your body’s hydration level. By the time you feel thirsty, you are two hours behind! Drinking something even the second you realize you are thirsty means that you will still be dehydrated for at least two more hours.
In fact, most people spend a good portion of their life mildly dehydrated, so drink water frequently even if u r not thirsty may be only sips but please drink water.