Answer:
The 8 of us go forth and not back to protect our king from a foe's attack. What am I?
Never ahead, ever behind, yet flying swiftly past, for a child, I last forever, for adults, I'm gone too fast.
Four leaves I have.
Travel a mile and I will change, travel a million and I will end as I started. What am I?
I reach for the sky but clutch to the ground. Sometimes I leave but I am always around.
No matter how little or how much you use me, you change me every month.