For the record, my 35mm f2 was purchased new, it was just out of guarantee period. And I'm certainly not sadistic with my lenses. If "oily blades" are a known issue, then why have Nikon apparently not fixed this problem at source? My oldest manual lens; a 55mm 1.2 Nikon, originally designed for the Nikon F, is still performing faultlessly, as is my (now) well used and marked, but extremely sturdy 35mm f2 manual, both purchased new in 1979. A 105mm 2.5 from the same series, still focusses with the silky smooth action typical of lenses of this period.
Yes, I understand, that if you want lenses that autofocus quickly, then some sacrifice has to be made re. the solidity of construction. I have now decided I prefer the long term reliability of manual focus, over the luxury of autofocus.