[Nosey]

I've briefly looked and searched but have been unable to find, probably not searching using the right words...

but, isn't there a way to turn the data off automatically after it's been idle?

I live in an area where I am roaming all the time and running the data is killing my battery, I swear in one of the roms I saw something that you could do to auto-disconnect the data connection if it was idle for so long