I say just ask your doctor, water intake is a lot different from say a 30 year old vs a 70 year old. And don't forget, being dehydrated can led to kidney stones. All I know, being under-hydrated can bring on headaches, fatigue, been there done that while working in the yard for long periods of time. And one way to tell, of course its not 100% but it will alert you to your needs. A way to tell if you’re drinking enough fluid is to check the color of your urine. If it’s pale in color and clear, you are likely well-hydrated. If it’s
dark-colored with brown tones, you may be dehydrated. And If you over do your sodium intake ( chips & salt laced goodies) , well you messed with your water intake. And those beers, although nice to have, are actually a diuretic, meaning that it causes you to lose more water through urination.