Simply put, the wood used for the Shortened Spear is a much cheaper type of wood (Fraxinus calradia) which is very susceptible to rot (especially due to Calradia's persistent monsoon rains) and must be shortened wherever rotting occurs on the staff. The wood used for the Spear, however, is harvested from the beautiful Quercus jessica alba, which is particularly resistant to rot and is very sturdy, unlike its acting career.