The answer is simple – drink enough fluid to keep the urine ‘watery’,  ie close to the color of water.  The academic answer is to keep the urine dilute enough so as to have a specific gravity close to that of water.  There are many avenues of fluid loss. Skin ( Sweating) , Lungs ( breath moisture) , Bowels (loose stools) , and kidneys. Poor drinking habits and medications, such as diuretics, can also influence hydration status.   Measurement of oral fluid intake by itself is an inefficient way to assess urine output. It is much easier and more accurate to simply tract the amount and color of urine produced. Dehydration will be associated with dark yellow urine, not uncommonly with a uriniferous odor. A well hydrated individual will have light colored urine with no odor. Avoiding concentrated urine lowers the risk of stone formation and infections. Regular cycling of urine in and out of the bladder greatly lowers the risk of these two problems. Emptying the bladder with a smooth coordinated stream avoids problems stemming from lack of co-ordination between the bladder and sphincter.