Answer:
I can fall off a building and live but in water I will die.
You do not want me when you donβt have me, but when you have me you donβt want to lose me.
I belong to you but others use me more often than you do
I'm at the head of an elephant and at the tail of a squirrel
I am bought by the yard but worn by the foot. What am I?
No matter how little or how much you use me, you change me every month.