Answer:
I always have to work with something in my eye. What am I?
If you've got me I'm everywhere. If you share me I'm nowhere. What am I?
Though I am only two words I have thousands of letters in me
I am heavy forward but backward I am not. What am I?
I can only be played on a windy day. What am I?
No matter how little or how much you use me, you change me every month.