Answer:
Alone I am 24th with a friend I am 20. Another friend and I am unclean.
I'm at the head of an elephant and at the tail of a squirrel
My tail is long, my coat is brown. I like the country, I like the town. I can live in a house or live in a shed, and I come out to play when you are in bed. What am I?
I go inside boots and outside shoes. What am I?
I have thirteen hearts but no body or soul.
No matter how little or how much you use me, you change me every month.