What you should do: If your phone is “unlocked,” meaning you can use other providers, get an international SIM card. I tested two this summer, Telestial’s Passport card ($20) and OneSimCard’s Standard card ($30). They have slightly different features, but each works more or less the same way. Your main phone number, once you insert the card, is not American.

For Telestial, it’s a British number; for OneSimCard, it’s Estonian. Telestial also provides you with an American number — OneSimCard offers it for $5 a month — that allows friends and family back home to text or call as if you had a local number. (You are charged 20 cents a minute to receive the call, though.)

Web browsing was surprisingly affordable in many places; in Scandinavia, it was 49 cents a megabyte on Telestial, which was enough to keep up with email, tweet regularly and use the occasional app or Google search. Prices have dropped recently, to as little as 10 cents a megabyte with a $99 bundle from Telestial or 25 cents a megabyte with OneSimCard’s Daily Data Package.

For pure Web browsing, install the Opera Mini app, a free, intuitive browser that saves money by compressing data to a fraction of what Safari or Chrome or many other mobile browsers do.

Most of the time, you can travel from one country to another and your phone is unfazed, simply switching from one local company to another. (Data rates will change, but you can find them easily online.) You load your phone with credits and set your account to reload automatically.

But the international SIM cards can be quirky. For instance, to make a call, you enter the number and press enter or send. The call is instantly disconnected, and sometimes weird codes appear on the screen. Seconds later, the phone rings. You pick up, and then it connects your call. It’s weird at first, but you get used to it. My biggest complaint, especially with Telestial, was that calls sometimes did not connect — and occasionally forced me to restart my phone to try again.

If that sounds too frustrating and you’re an AT&T or Verizon customer, consider their newly competitive international data plans. AT&T, for example, now offers $30 a month rates that allow 120 megabytes of usage in over 140 countries. The cost of voice minutes, though, is still very high and can’t compete with the international SIMs. A final note: Although the rates sound reasonable, beware. You can easily fall into your home habits and stay overconnected. Don’t. For a while, I was running through $10 or $15 of data a day.

•  The power users: You want connectivity 24/7, and you’ll sacrifice convenience — but not too much money — for it.

What you should do: Buy local SIM cards. It’s the cheapest way to go. But it’s also the biggest hassle. Make that hassles.

First, you’ll need to research and compare domestic companies’ rates and coverage for each country you’re visiting.

Then once you find a place to buy the card, you’ll have to activate it and get used to its systems (for dialing, adding credit, and so on). If credit disappears faster than you think it should, there’s little recourse. (The companies mentioned earlier have excellent U.S.- or Australian-based customer service.)

Finally, while in some countries getting a local SIM card is as simple as handing cash to a street vendor, in others you have to fill out paperwork, provide documents and sometimes even travel across the city to register and activate your account.

•  The addicts: You looked up from your smartphone once, and you didn’t like what you saw. Your greatest fear is that you’ll die and find out that heaven doesn’t have a Wi-Fi connection.

Unless you just won a mega-lottery, forget about foreign travel for now. Head to some cozy spot in the U.S. where you and your smartphone can spend some uninterrupted quality time together. Find a cafe, check in there on Four Square, snap a picture of yourself and post it to Instagram, and remember not to leave before praising your latte’s foam design on Yelp.

A trip abroad can wait, because, while there are a few companies that offer international plans for “Mi-Fi” devices, a sort of mobile hot spot with large data allowances in specific countries, they are still prohibitively expensive for budget travelers and won’t cover you everywhere anyway.