I think his problem is that the sticks are getting stuck in the hose before they get to the impeller, not that the impeller can't digest them. Yeah a new impeller will pull a bit harder because the tollerances are tighter, but I don't that it will solve his problem unless it's really worn. I think the answer is to try to leave the larger sticks behind and go back with a barrel and pick them up if you're doing the cleanup yourself. For customer piles, it's always a good idea to feed with a rake or shovel...you never know what's in there. Sometimes you can clear a stuck stick by sending a pile of crap at it, but of course it sometimes just clogs it more. Never had a clog I couldn't clear by giving the hose a straighten, jiggle and slam though.