key is to look at the chrome plating on the lH side - is it worn through. The bends can be straightened if cosmetics are important - probably will see no difference in performace. Check the level of the concacve as well. ThlH side wears quicker than the rh side especially if the unit has std bars and helicals and no helical extension (triangle welded in on upper rh side of infeed area front of solid cage portion to prevent secnd pass threshing.) On many trade in machines we will pull the cylinder, weld up the worn sections of the threshing grate - grind down to level then add hard surfacing - ususally lasts 1000 hours or so and all done w_o removing grate. All one needs is a decent welder who is not claustaphobic.