If you decide to sell or give your laptop, smartphone, tablet or device to someone else (or to just put out in the electrical waste), you should first perform a factory reset. This will return the device to its original settings, and should also remove all your personal data from the device. Check your manufacturer’s website if you need to find out how to perform a reset.
You wouldn’t want someone gaining access to your data, or being able to access your bank accounts and other resources.