Just as you might pare down to the bare minimum with your luggage, do the same with your wallet when traveling outside the country. Though the possibility of losing (or being relieved of) a wallet isn't necessarily greater abroad than in a densely populated city at home, it's far more complicated logistically to recover from such a loss.
Here are some basics on what travel-security experts say to take and what to leave behind:
The wallet pare-down: Before you leave, take out all the receipts, business cards, supermarket loyalty cards and assorted other ballast that you carry every day.
Cash: Never carry excessive amounts; take only as much as you think you'll need. Leave loose change at home. It's just a hassle.
Foreign currency: Use an ATM at your destination airport to secure a small amount of local currency for transportation to the your hotel, tips, snacks, etc. Debit cards often are cheaper to use, with minimal exchange fees, and you can reload on cash as you go.
Credit cards: Take no more than two credit cards, one in your wallet, the other in a safe place. Choose ones that are widely accepted and have the lowest foreign-transaction fees. If you use plastic for purchases over $50, you won't need to pack wads of cash. Also, photocopy the fronts and backs of your cards and stow away in a safe place. This way you know what to cancel and who to contact if they are lost or stolen.
Identification: Carry at least two types of ID. Keep your driver's license or a state ID card in your wallet. Your passport is the other form of ID. Also photocopy these and keep the copies in that secure place.
Each time you use your wallet, return it to the same safe location as soon as possible. Stash a small amount of extra cash and the second credit card in a deep pocket somewhere, just in case you lose your wallet.
Health and insurance information: If you buy travel health insurance, carry your card. Also include a list of any medications you take, using generic names. Keep a copy of how to contact your next of kin or contact person, plus your doctor's name.