High-tech cell phones can store more than just telephone numbers and appointments. Today some people keep super sensitive information and some customers end up passing that along to another customer when they trade in that phone.
To help avoid becoming a victim one expert says you must be sure to completely erase stored information like bank account numbers and pin codes from your phone before you get rid of it.
It's just like a computer you could delete messages and send them to your deleted files but that doesn't change the fact that they're still on your computer.
And anybody with any savvy can get into your phone and dig stuff outta there and get stuff that you don't want people to have.