Melbourne

@SituationCake
I learned this from a person whose job it was to clean Panavision lenses, which cost astronomical amounts of money: The problem with the cloth is that any dirt it picks up ends up getting rubbed all over the glasses. This is particularly bad when there's dust that might be abrasive, you're basically sandpapering the lens. The way he showed us was: one lens tissue, one wipe, in the bin.
Unlike a Panavision lens, glasses don't cost as much as reasonable sized inner city apartments, so you can probably get away with using a disposable wipe each session, or if you're worried about the baby seals and shit, a clean cloth each time (I use a clean cotton hanky).
The more care you take making sure that what you're cleaning them with isn't full of grit, the longer they'll stay clear.
@YarraByte