Building and update Blender

Hi chaps,
I’ve got a couple of questions about blender and its installing process:

  1. 10 reasons why do I need to build Blender ?
  2. Ok, I compiled and installed Blender , How to update it with new release?
  3. I remember when Blender Institute was working on Sintel there was a video about auto update script. So if ther is a new version of Blender this script will recompile the Blender.
    Where I can find it?