How to delete your data from your gadgets BEFORE giving it away..

The idea for this came from the old Iphone 3GS that has a bad motherboard. Gazelle will give me $10 for it, but have been to lazy to box and mail it. Nevertheless, if you are not as lazy as me in this regard, this is what you should do before giving away any gadget to make sure your personal business stays that, YOUR personal business.
You could try deleting individual apps and contacts, but the odds of doing that effectively are close to zero. Instead, you want to do a complete reset of your phone to wipe out its data and restore it to its factory settings.
How you do this varies from operating system to operating system, and sometimes even device to device. These are general instructions that should work with most devices; however, it's best to check with your manual or manufacturer just to make sure.
Android: For versions before Android 4.0, press the Menu key from the Home screen and select Settings/Privacy/Factory data reset. You'll get a warning screen. Scroll toward the bottom and tap "Reset phone." If you also have an SD card in the phone (and don't want to use the data in your next phone), also make sure to check the box next to "Erase SD card."
For Android 4.0 or later, go to Settings and look for "Backup and reset." Tap that, and then, on the next screen, tap "Factory data reset." You'll get a warning screen along with a list of all the accounts you are currently signed into.
iOS: Go to Settings/General/Reset and then tap "Erase all Content and Settings." (This is specifically for Version 5; the process may differ slightly for other versions.)
Windows Phone 7: Go to the Home screen, then tap the Application Menu Key and select Settings/ System/About/ and tap the "Reset your phone" button.
BlackBerry: Head to Options/Security options/General settings, and then tap menu. Then select Wipe Handheld.