Answer:
I am commonly ate before I'm born and after I'm dead.
I contain five little items of an everyday sort. You can find all five in a tennis court.
Six letters do my name compound; among the aged oft I'm found; The shepherd also by the brook hears me when Leaning on his crook; but in the middle me divide and take the half on either side each backward read a liquor tell ev'ry gay toper knows it well.
What is always in front of you but can't be seen?
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it, can't see it. What is it?
No matter how little or how much you use me, you change me every month.