Many phone companies have promotions that allow you to trade-in your old smart phone and give you credit on a new smart phone. The problem is that you don’t want anyone else to have access to have ALL your personal data on that old phone.
Shannon Morse of Tekzilla did an interesting segment on Tekzilla on what was the best way to wipe all that information off her Nexus 4. She talked about rooting the phone and then installing or buying apps, like SecureWipe and Hexzmob Recovery Pro, that would theoretically wipe the phone. The problem was they didn’t worked. She used an app call Diskdigger which easily found her deleted/wiped files.
She makes the point that just because you delete a file – it’s really not gone – it’s still on your phone.
What Shannon did find out was that using the normal Google factory reset directions, it will erase and wipe all your old data. That’s all you need to do – no rooting required.