Answer:
The older they are the less wrinkles they have.
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.
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
Round like a dishpan and smaller than a bathtub. But the ocean can't fill it. What is it?
Useful tool for who in darkness dwell. Within you, corrupting like a deadly spell.
I have two eyes in the front and a lot of eyes on my tail