Answer:
What has been around for millions of years but is never more than a month old?
What fastens two people yet touches only one?
I am partially baked. I am not completely lit. I am a portion of the moon. I am lesser than full wit. I am a divider of the hour. I am not a total lie. I am a sibling through one parent.
I have one eye, See near and far, I hold the moments you treasure, And the things that make you weep.
Sometimes imaginary and sometimes real, sometimes they are the closest and dearest person outside the family. Who are they?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?