Answer:
I go inside boots and outside shoes. What am I?
I can be in your body but never on your placemat. I'm always better when I'm fresh, but you'll never see me in the flesh. What am I?
I am a certain five-letter word and become shorter when you add two letters to me. What am I?
I have a head tail but no arms and legs.
I run cold and hot, I look blue but am red. What am I?
No matter how little or how much you use me, you change me every month.