When I got my Craftsman 6000 ZTR mower, the mechanic said it had sealed bearing so I never really checked the spindles till the second year I had it. I then saw the zerks and began pumping grease into them till it came out. It took a tube and a half total for all 3 spindles to get grease to come out the spindle. That was beginning of this season and I havent greased them again. I figured that if it was good for a year without any grease, 20 oz ought to last for this mowing season. It takes me about an hour to mow and about once every two weeks so I dont think I put more than 12 hours per year. I no longer wash it off after use, just take a leaf blower and blow off the grass debris after use. Someone told me that washing allowed water to get into the bearings due to the way the spindles set in a depression in the deck, so I quit washing. Time will tell if this has any effect.