If you lose your wallet, you can use your phone to call the places you've been and ask if they've found it. Never assume it's really gone until you've checked.

Once you're certain the wallet is gone for good, you'll want to cancel your credit cards by phone within 24 hours. Start with store cards, because they stick it to you more than credit card companies do when cards are lost. Call the bank to report any missing debit cards. That reduces your liability to US$50. If you don't call within two days, you're liable for $500 (or more if you don't call within 60 days after receiving your bank statement).

Food and Shelter

You can survive without water for about three days, and without food for up to a month. But in a city, you probably won't even have to skip a meal, as long as you can get your hands on money.

It's a great idea to fold and tape a $100 bill to the removable plastic cover of your phone's battery compartment. If you lose your wallet, cash is always nice.

Another way to get cash is to get it wired to you from your spouse or someone else back home via, say, Western Union. (Use GOOG-411 to find the closest office.) ID is generally required, but if you don't have one, you can simply give the money transfer number (which Western Union assigns the sender).

You can also survive without cash by checking into a nice hotel. The better the hotel, the more of your survival needs can be met without actual money.

Hotels always ask for your credit card and ID when you check in. But they don't really need it. Most hotels are willing to accept credit cards over the phone. They often tell you that it's against their policy. But explain your situation, and they'll probably do it. If they absolutely refuse, then find another hotel.

Once you've found an accommodating hotel, just have your spouse or someone else with a credit card call the front desk while you're standing there, and the hotel can process the transaction over the phone.

After you've checked in, your chances of survival increase exponentially. You can eat by ordering room service, and bill other services, such as car or taxi service, to your room. (Arrange all this through the front desk.) You can use the computers in the business center. Importantly, the hotel gives you an address to which your spouse or someone else can overnight credit cards, clothes or anything else you may need.