My parents used to make me write on the calendar when I put in lenses so I'd throw them out in a timely manner. Now, here, in CA, the air is so crappy they start to get all coated with protein after about 6 weeks or so and have to be replaced, because they hurt like hell. However, I will say the CibaVision ones at $100 for 12 pairs last longer than the Bausch and Lomb ones at $300 for 12 pairs. Cost doesn't always equate to longevity.

Yet, my thirtyninedollarglasses.com glasses are as ghetto as ever.