When it’s time to buy a new phone, you know the routine: Contact your cell carrier, choose one of their phone options, and add the payment for your new device to your monthly budget. Some consumers, however, take a different approach by buying an unlocked phone that — in theory, at least — allows them to switch mobile providers whenever they like, to keep up with the best prices.

Reader Melissa Anderson of Rowley wants to know whether the potential benefits of an unlocked phone outweigh possible drawbacks. As is so often the case, the answer is a solid “maybe.’’

First, the basics. Most phones that are purchased directly from a mainstream cell carrier are locked — they can only be used on that one company’s network. An unlocked phone can be switched from one network to another. You can buy an unlocked device in many places, including on Amazon, at Best Buy, or direct from the manufacturer.

At first, an unlocked phone can seem like an expensive choice because you generally pay the whole cost up front, rather than spreading it out into monthly payments. But buying an unlocked phone means you can choose from a wider range of devices than just what is offered by your carrier, says Sascha Segan, mobile analyst for PCMag.com. More choices mean you might find a phone that offers the features you want at a lower price; Segan points to the ZTE Axon 7 and the OnePlus 3T as good values.

Also, using an unlocked phone can be a great money-saver because it allows you to take advantage of the low prices offered by small carriers like MetroPCS and Ting, and to switch providers when a better deal emerges.

An unlocked phone, however, does not offer complete freedom, Segan notes. The majority of phones sold unlocked work only with service from AT&T, T-Mobile, or the smaller carriers that use those networks, he said. Only the unlocked versions of the Samsung Galaxy S7, Google Pixel phones, Moto G4 devices, and some iPhones will work on Sprint and Verizon as well.

Most carriers will unlock a phone you bought from them after it is paid for or after a set period of time, but beware: Even unlocked, many of these phones are designed to work poorly or not at all on other networks — it’s an insidious way to keep you tied to your original provider. Research your individual phone before counting on this version of unlocking.

Have a consumer question or complaint? Reach Sarah Shemkus at seshemkus@gmail.com.