Answer:
I am a cave full of bones and the house of a worm.
I am an activity involving pins flying in the air.
I must be broken before you can use me.
What kind of dog keeps the best time?
Kings and queens may cling to power and the jesters may have their call. I am the most common but I can rule them all. What am I?
No matter how little or how much you use me, you change me every month.