I have carried two cellphones from two difrent providers that I paid for on my own. Meaning I was paying a LOT. I kept two for several reasons.

First: when one didn't work the other almost always had a signal
Second: one was my GPS phone, and the second I could talk on using my head set.
Thrirdly: for a while my cellphones were the victums of some very unfortunate accidents! so haveing a spare saved my but several times.

Eric