how much urine does the bladder hold? how much urine should

how much urine does the bladder hold? how much urine should be left in the bladder after going to the bathroom? why would the bladder not empty out completly?

The bladder holds between 12 and 16 ounces of urine. Normally you will feel the urge to void when the bladder contains about 8 to 10 ounces of urine, about as much fluid as in a can of soda. There really are no “normal” voiding patterns. Patterns which do exist range from every 4 to 6 hours to every 6 to 8 hours. Seniors over 65 may void every 3 to 4 hours and at least once during the night. After voiding there should be around 3 ounces left in the bladder