i agree the poly paddles will speed the wearing of the housing.. I decided I wanted the extra capacity of the polys.. I installed 2 poly paddles on the clean grain and return elevators.. they are installed so when one is at the bottom the other is at the top of the elevator.. this seems to have the effect of clearing the chain. and when working in tough conditions or with damp grain I have no build up of mud in the elevator.. plus there isn't the wear from a chain of all poly paddles..