well, i have (maybe fortunately as i can’t afford one) no experience with nikon coolscans but i think the results i get from my canon flatbed are really good value. i bought it two years ago for 90€ (which is kind of half price because the newer model was already on the market when i [...]

i think the only “damage” would be that the grease becomes hard and sticky after years or so. but the screw thread is of course very accessible for a little cleaning