Most seasoned Nexus device owners already know this, but the Nexus 5 (and 6) feature all of the radios and bands for the major carriers in the United States. This means that a SIM card from Sprint, T-Mobile, AT&T, Verizon, and other providers will work on the Nexus 5/6 (though Verizon has blocked the Nexus 5 for no reason). It doesn't matter if your device was purchased from a carrier because Google mandates that Nexus devices are sold factory unlocked no matter who is selling the device. Few phones come with such flexibility, and you won't have to worry about moving your Nexus from a CDMA carrier to a GSM carrier and vice versa. Also, you won't have to tell a carrier that you're switching or jump through hoops like with other devices.