We usually buy the local currency from Wells Fargo before we begin our trip. We've never had a problem until this trip to Mexico. It turns out that Wells Fargo sold us many bills that were ancient currency, and when we unknowingly tried to spend it, we were told the establishments could not accept the money. Not a huge deal, just extremely annoying. You would expect that a huge financial organization like Wells Fargo would know better. From now on we will use in country ATMs.