You've got to ask a lot of questions. You've got to probe for all possible kinds of charges. Don't be surprised if a customer service rep passes you off to someone else. Once you've tracked down the fee policies for all the different kinds of plastic in your wallet, you'll be able to decide which cards to take with you and which ones to leave at home. You'll definitely want to bring a card or two on your overseas adventure.
Credit cards are still a great way to pay while traveling.
Exchange rates offered by credit cards are better, often a lot better, than those offered at a currency exchange counters and even at overseas banks. The exchange rates secured by Visa and MasterCard are based on wholesale rates offered to large banks and corporations rather than the retail rate offered to consumers. Ditto for exchange rates on debit cards, such as the Visa Check Card and MasterCard Money. Even with those pesky surcharges thrown in, paying with plastic is still cheaper than converting cash overseas. The same thing happens with traveler's checks.