Answer:
I am always hungry I must always be fed. The finger I lick will soon turn red.
I go from house to house a messenger small and tight. Whether it rains or snows I sleep outside at night.
I am enjoyed by some despised by others. Some take me for granted some treasure me like a gift. I last forever unless you break me first.
I produce wool and spit a lot
I am constantly overlooked by everyone but everyone has me.
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.