Here's why you should wipe your device before trading it in

Our devices have a lot of information about us, and we give them more and more every day. The information stored within our smartphones and tablets also links to a bigger entity, stored in some mysterious cloud somewhere. When you give up a device, either selling it or via trade-in, do you clear all the data? Here's why you should — and how.

Recently, AT&T admitted that some third part vendors had accessed customer accounts without authorization. Via devices traded in or sold to them (it's not exactly clear how they came to have devices with customer info on them), a few employees took the liberty of accessing customer information via their accounts. By requesting unlock codes for the device, the vendors aimed to resell them.

The problem is, once unlocked, they had unfettered access to customer data. Aside from the immediately curious picture and messaging issue, they were also given access to the Customer Proprietary Network Information. That's essentially all the necessary info relating to your account.

To be clear, this breach happened via at least one AT&T authorized reseller, not a company store. Even at that, there are some precautions you should take ahead of giving a device up.

Back your data up

Always have a backup of data. If there are pics on the device, sync them to the could now and then. Google+ Photos will automatically copy your pics and video to the cloud, leaving you to snap away and not worry about losing info. Making sure contacts are synced to an account (like Google)is also a good way to not have to worry about losing info when you give up a phone.

Clear your accounts

Recently, a friend gave me a phone to trial for a bit. It was a device he had been using, and did a factory reset ahead of handing it over. While that seems adequate, it wasn't; his Facebook and Twitter accounts were still active on the device. I had to start fresh, sure, but his accounts were still there.

Ahead of doing a factory reset, go through and delete your accounts in the settings. Also be sure to clear your browser cache and history, just in case. By deleting your accounts ahead of wiping the device of info, you're creating a two-step safeguard. Better safe than sorry.

Do it again

Factory reset, and the screen pops up with the "Hi, select your language" screen you see when purchasing a device for the first time. While that seems adequate, it may not be (see above). Go ahead and select a language, but don't enter an account. Meander through your soon-to-be-ex phone and see if anything lingers. Did a picture somehow not get deleted? Are there messages in the stock messaging app, or contacts on the device?

Check to see if any accounts remain for some odd reason, and delete anything that remains manually. Do another factory reset if there is still info you don't want anyone getting hold of, and check it again.

It’s important!

Take a few minutes ahead of selling or trading in a device and make sure you know your info isn't there. If a salesperson gets snippy about your exercise, walk away. If you're selling it on eBay, Craigslist, or a site like Swappa — do these steps ahead of listing it. Once it's purchased, someone likely wants your device asap, and it's better to have it done so you're not stressing at the last-minute.