Breakage and deterioration of Plastic/Poly drains is mainly caused by UV Rays and oxygen exposure. The deterioration process begins almost immediately after manufacture causing plastic/poly to become brittle over time, as seen in the first image.  This is a very common problem with poly type drains.

Both of the drains below were installed four years ago in very close proximity to one another.  LTEC drains will out last any plastic or poly drain as seen in the second image.