Not necessarily. Most cell phone providers allow you to transfer a carrier-compatible device. However, if you haven't yet paid off your current phone, you may need to do that, unlock the device, put in a new SIM card, and pay an activation fee before switching to your new carrier. And sometimes early termination fees and restocking fees from your previous carrier apply. On the other hand, some companies offer trade-in deals that incentivize purchasing a new phone by paying off your old one.