Answer:
Fashions change, but what can a person wear that is never out of style?
Blade to blade I always win My foe laid low and even. Yard by yard through thick and thin I'm busiest in season.
You use me from your head to your toes. The more I work, the thinner I grow. What am I?
I roam through the lands hoping to rescue my love. I search high and low and will stomp on you if you get in my way!
There is one in every corner and two in every room.
I open wide and tight I shut, Sharp am I and paper-cut fingers too, so do take care, I'm good and bad, so best beware.