Answer:
I am long and slim works in light. Has but one eye and an awful bite.
You throw me out when you use me and take me in when you are done.
Use me if you really want to see inside someone
Marking mortal privation when firmly in place. An enduring summation inscribed in my face.
I am the place where yesterday is always before today. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.