Mellotronists

Yeah Martin,
 
That's all well and good, but what about the benefit of grinding pinch  
rollers as opposed to replacing them with new ones? Could you please place  your 
answer within the constructs of a cost based flow analysis versus  the time 
delay / extra-continental materials acquisition method, taking into  account a 
needs vs. wants vs. "likes" approach so that we can all feel a little  more 
comfortable?
 
Bud