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?
In the 20 years I've owned glasses, I've never had an issue just using my shirt.
Same I don't have to wear glasses anymore, but it's was t-shirt all the way. And the occasional "I'll pour water on the lenses to make them more clean".