Answer:
No matter how little or how much you use me, you change me every month.
I am never quite what I appear to be. Straight-forward I seem, but it's only skin deep. For mystery most often lies beneath my simple speech. Sharpen your wits, open your eyes, look beyond my exteriors, read me backwards, forwards, upside down. Think and answer the question...
Some try to hide, some try to cheat. But time will show, we always will meet. Try as you might, to guess my name. I promise you'll know, when you I do claim.
How far will a blind dog walk into a forest?
What do you fill with empty hands?
What language does a billboard speak?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?