Answer:
I can be found in seconds, minutes and centuries, but not in days, years or decades.
What must be looked through in order to see?
What leaps one time out of four?
What gets bigger the more you take away from it?
It keeps you on the ground and stops things from floating around. What is it?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.