Laptops, camera chargers, cell phone chargers and iPod chargers will work fine as long as you buy a plug adapter that allows you to plug devices made for the U.S. market into the wall sockets in other countries. The reason for the plug adapter is to convert the plug from the flat metal prongs used in U.S. power outlets to the round metal prongs used elsewhere. As long as you have the plug adapter, you don't need a special power supply for your laptop, use the one that came with it. The plug adapter will read "Input: 100- 240 VAC 50/60 Hz." That tells you it is made to work either with the U.S. electrical system or the system in Europe. You shouldn't need a separate voltage converter to go from the U.S. 100 V to the European 220 V, for example.
Then next piece of advice is to buy or rent a "World" or GSM-compatible phone that works outside the U.S. Frequency bands vary by country so your mobile carrier can offer you one that will work with the country you're visiting. If you're going to be in one country for an extended period, you may wish to consider getting a local phone with a pre-paid SIM card. This might be less expensive than using your World phone and paying the roaming charges. See also:
I want to get a phone that I can use outside the United States. What should I look for?
Finally, be alert to a payment-related inconvenience that's on the rise: Old magnetic stripe cards not taken for purchases. This is happening at transit ticket machines, highway tolls, gas stations and small merchants, where you can only pay with chip-and-PIN cards, a security measure adopted around the world to prevent card fraud.
American credit card holders have found that their cards won't work at unattended kiosks. For example, the automated ticketing machines at train stations and the Vélib bike rentals. The reason is the equipment is designed to only work with payment cards that have an EMV chip, rather than the magnetic stripeand you don't have an option. EMV is a secure payment standard adopted by MasterCard, Visa, American Express and JCB to ensure that credit cards with chips in them work with point-of-sale terminals and ATMs anywhere in the world.
More often than not, the kiosks won't even take cash because a goal is to eliminate cash and coin management and vandalism. So that can affect metro and train tickets, highway toll booths, gas pumps, parking garages and other places where there are no cashiers.