Answer:
The more you work the more I'll eat.You keep me full I'll keep you neat.
I am always hungry I must always be fed. The finger I lick will soon turn red.
Against the sun I protect your eyes and am often worn on the face of spies
Until I am measured, I am not known. Yet, how you miss me when I have flown. What Am I?
The more of me there is the less you see.
The profession of Jimi Hendrix and Eric Clapton