Answer:
Men seize me from my home tear apart my flesh drink the sweet blood then cast my skin aside.
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
What type of shoes do spies wear?
I am heavy forward, but backward I'm not. What am I?
Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.
No matter how little or how much you use me, you change me every month.