Carolinian
TUG Member
You always need some local cash for small purchases, tips for taxies etc. And...I am always a bit leary about leaving my credit card info all over a foreign country. Yes, I know I won't be responsible for unauthorized charges when the dust all settled but it's a pain in the butt to go through all the hassle of cancelling cards, proving you didn't make the purchase etc. etc.
One place many people do not think of to get local currency is airport shops. In most airports I have been in overseas, you could find many shops where you could make a purchase with US dollars and get your change at a decent rate in local currency. The exchange rate generally beat the heck out of the currency exchange booths at the airports which have a notoriously bad exchange rate (exceptions I have found were Mexico City and one of the two terminals in Zurich where airport exchange kiosks gave decent rates and no commission).
Indeed, occaisionally this works outside of airports. I remember that in the pre-euro days, Luxembourg city had no exchange houses where one could exchange at a decent rate. The best bet was to go to the McDonalds in the city center, buy something and give them a 50 or 100 in US money and get change at a very good rate in Luxembourg francs.