Lens manufacturers say that anything other than a microfiber cloth will damage the coatings on a lens. But microfiber cloths eventually pick up crap and they look like they're a pain to wash.
How do you keep your lenses clean? Are you using cloth/kleenex or microfiber cloths? If you use microfiber cloths, how do you clean those?
Daily wash with water and foaming hand soap. Foaming soap on lenses, rub with fingers, rinse. Dry with cotton hankerchief. I usually keep my glasses 2 years before replacing and haven't had any issues with the anti-reflective coating washing this way.