I can almost understand Aaron's glasses situation from the perspective that he finds new glasses on the black market (collected from corpses or looted from closed up eye clinics) that while not perfect for his current vision are good enough. I usually have 3-4 pairs of old prescriptions on hand that I could get by with in a pinch until I get around to donating them (the lenses generally don't have any scratches, though they do get cleaned up before being sent to third-world countries).
I actually have a bigger problem with the Spanglish, unplugged versions of classic rock songs in this show. All the musicians they showed in Mexico were way too young to know the original versions, and they'd likely be unable to learn how to play them like that from dug up sheet music alone.