Answer:
u always follow me but I am rarely seen
I am perfect with a head perfect without a head; Perfect with a tail perfect without a tail; Perfect with either neither or both.
I destroy your home from the inside out.
What loses its head in the morning but gets it back at night?
I am rarely touched but often held. If you are smart you'll use me well. What am I?
Give it food and it will live, give it water and it will die.