Answer:
No matter how little or how much you use me, you change me every month.
who do you think you know but sometimes you don't
A tiny bead, like fragile glass, strung along a cord of grass.
A hole in a pole, though I fill a hole in white. I'm used more by the day, and less by the night.
What travels from house to house and is sometimes narrow and sometimes wide but always stays outside?
What sphinxes employ and players enjoy.
Difficult
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?