It s material dependent, when using a silky smooth material such as straight Portland cement very little wear will occur but If using a product that is very abrasive such as Euchoshot or with silica fume then maybe just a few hundred bags. Routine maintenance should be performed at the end of each work day to ensure that the rotor & stator are well calibrated. Tip-- To calibrate the stator, fill the hopper with water, set the speed to 50Hz, attach the material hose to the end of the pressure gauge. Kink the hose as you would a water hose and turn on the pump. The pressure gauge should read 120 to 140 PSI. if not then tighten evenly the 3 adjustable bolts on stator. If the pressure can t be reach then it s time to replace rotor and stator.