Used their on-site optometrist who wrote a prescription for one year (wasn't aware of the one year until today).  I broke my prescription sunglasses and it has been 14 months since my exam and I can't get new sunglasses without paying for an exam because my insurance covers and exam every two years.  Now I know to ask about the optometrist's expiration date prior to scheduling an exam.  I've lived all over the country and never had a lens prescription expire in 12 months!  Also, I paid substantially more for the glasses at lens crafters!  Most of my scripts either didn't expire or expired in two years!  I don't believe AZ requires the script to expire in one year.....just a ploy to get more money.  I'm pretty sure people are wise enough to schedule an exam when necessary.