Answer:
You use me between your head and your toes the more I work the thinner I grow.
I run around the streets all day. Under the bed or by the door I sit at night, never alone. My tongue hangs out, waiting to be fed during the day. What am I?
Soft hairy from door to door. I am the pet that always stays on the floor.
I am owned by Old McDonald.
I can fall off a building and live but in water I will die.
No matter how little or how much you use me, you change me every month.