Watch out for Costco: you get what you pay for, plus some extra damage. I got my lenses replaced there, and they needed to be adjusted once they got back from the lab. Not a big deal and entirely expected. However, the first saleswoman they had help me, Marilyn, automatically bent the frames ("boxed off" in her words) back to being perfectly symmetrical, consistent with the shape she thought frames should be. The fatal flaw in this reasoning is that people don't have symmetrical and even faces, as any eyeglass professional I have encountered in my 12 years of wearing glasses (no contacts, just glasses) knows. She spent little time trying to diagnose the problem, and thought they could all be solved by twisting the nosepads. Since she had no success, at times making them worse. Also, after using the machine to heat them to make the metal bendable, she gave them to me to put back on immediately, thus burning the sensitive skin behind my ear. This, again, has never happened to me with any other place, whether it's an eye doctor or free-standing eyeglass boutique.
Finally, she referred me to a second woman, Rebecca, who saw them on my face for 0.2 seconds, then slammed and bent the frames to be even (really, what is it with you people?!) on the table, and they were the worst I fit that I have ever experienced. The frames were wavy, metal twisted, and squeezed my temples. The metal is irrevocably damaged, and I need to return to speak with the manager tomorrow. Rebecca became defensive after I told her to stop working on them, saying "I've been here just as long as Marilyn" and huffing off with an attitude. This complete lack of customer service compounded the damaging incompetence I witnessed. My hands were literally shaking with helpless rage as I watched her destroy my Fendi 662's (not purchased at Costco), and I regret not stopping her. But, when Costco installs employees behind an optical counter, you expect and trust that they're professionals. They're not.