I turn off data when traveling international. I was recently in Canada and could text free (included), but data was pricey, so shut it off when not needed.
I also go to France often enough that I bought an Orange France Domino for wifi and run all my data through that, but can still get calls on my US phone number. I just shut off cellular data and avoid VZW int'l data charges everywhere in France.
I'm still on iOS 6. So, am I to understand it's not possible to shut off cellular data on iOS 7?!
No it is possible. There is now something called control center that allows quick and easy access to certain settings toggles (Bluetooth, wifi, airplane mode, do not disturb, and orientation lock). None of them are cellular data controls but the poster would like it to customizable so they could select this as an option. To do it now you have to do it as before through by accessing the settings>phone>cellular data switch and then changing it there just as before.