Answer:
I run smoother than any rhyme I love to fall but cannot climb.
I follow you all the time and copy your every move but you can't touch me or catch me. What am I?
I'm tall when I'm young and short when I'm old. What am I?
I am all around you but you cannot see me. I have no throat but you can hear me. Valued during summer but despised in the winter.
I have two bodies joined together as one. When standing still, I run and run. What am I?
No matter how little or how much you use me, you change me every month.