This is mainly aimed at Kurt, but if anyone else knows the answer then feel free to give me a reply too...

i see Kurt likes to stress that we should avoid faces that have 5 edges to it or even 3 faces (although unavoidable at times, like he says)
but why? i thought maybe it had something to do with the planarity of faces (btw, wheres the 'keep faces planar' option in maya 8.5?) but then clearly, as i have seen far too often, faces with 4 edges can also become non planar.

so why stress that we only have faces of 4 edges?