Answer:
You cannot keep me until you have given me. What am I?
In my life I must bare, my bloodline I must share. What am I?
Two bodies have I, though both joined in one. The more I stand still the faster I run. What am I?
I hop around and deliver eggs at Easter.
I have a few points but we're not competing. I'll help you win when you're eating. What am I?
No matter how little or how much you use me, you change me every month.