It happens all at once and yet slowly over time like water licking a rock until it is a smooth round pebble. 

The layers of you that need to be shed like a snake's dead skin slip from your body revealing a new incarnation of you with unblemished skin and better eyes with which to see the world.  It is easy, sometimes, to bury the dead; you move or get a new job and the life that came before it is gone, a wisp of memory that your reborn self can look back on and be happy she is no longer there. 

Yet there are those old selves that no longer serve a purpose, the selves that need to be put to rest but are all too easy to keep around because, dead as they are, worn and gone, they are comfortable if only because they are what you know. They are the threadbare and ill-fitting coat that you know you should give away--but that would mean you'd need to find another skin to fit your frame just so...and that takes time and energy, those things you are half-afraid you don't have enough of.  They are the ghosts that keep you company at night, the ones that won't leave until you want them too, the ones you don't even know you're keeping around until one day you stop, having stumbled into an old life, a space you would never willingly enter now.

Then all at once you see how you have been holding on so tightly and yet now find it is harder to keep holding on than it is to let go.  The threadbare coat has finally fallen apart from overuse.  So you gently pry your hands loose from those past selves--those final stray strands--those versions of you that are no longer you, and embrace this new skin.  It is, after all, the only one you need.