Why you may want a backup SIM

Many of our favorite phones support more than one SIM at a time, giving you two phone networks on your phone. Some carriers lock their phones so that you can only use their SIMs for a limited amount of time, but can be unlocked after a few months. If you bought your phone unlocked or have had it long enough that it's now unlocked from your carrier, adding a plan can be as simple as downloading a new eSIM. You could also use a physical SIM if your phone has an open slot.