Before you erase the device
Make sure you have a backup copy of all the personal data you want to keep. Many newer devices have a backup and restore function that will enable you to transfer your data from your old device to your new one.
Make a note of the websites you a frequently logged into so you can log back in on another device.
If you use your device to control any of your smart devices around the house, make sure you're able to manage them using a different device.
If you use your device to verify online accounts (e.g. confirmation SMS codes), make sure you are able to do it from another device.
Erasing the data on your device
The best way to make sure that your data is completely erased is to use 'Erase all content and settings' or 'Factory reset' options on your device (the name of this feature will depend on the type of device you have).
This should remove all your personal data from the device (including messages, contacts, photographs, passwords, and any apps you may have installed).
To find out how to use this feature on your specific device, refer to the device's instruction manual or manufacturer's website.
You may be given the option to keep your personal files when erasing your data. Make sure you don't choose this option if you're selling, trading in or giving away your device.
Here are some useful links to help:
Reset your Android device to factory settings - https://support.google.com/android/answer/6088915?hl=en
Erase your Apple iPhone, iPad or iPod Touch - https://support.apple.com/en-us/HT201252
Reset your Chromebook to factory settings - https://support.google.com/chromebook/answer/183084?hl=en-GB
Start afresh with a clean installation of Microsoft Windows 10 - https://www.microsoft.com/en-gb/software-download/windows10startfresh
Restore your Apple Mac to factory settings - https://support.apple.com/en-gb/HT201065
Websites last reviewed: 05/10/2021
Choosing a second-hand device
You don't need to buy the latest or most expensive model to stay safe, but avoid buying devices that are no longer supported by the manufacturer (or where support will end soon).
If you buy a device that is no longer supported it won't receive updates that contain new features and performance improvements or security updates from the manufacturer.
Check online for supported models of the device you intend to buy.
Before using your second-hand device
Perform a factory reset - it will remove the previous owner's data and ensure your phone is in the best possible state before you start using it.
Switch on automatic updates and use security measures such as passwords, fingerprint or screen-lock to secure your device. You may also wish to set up automatic backups for your data in case the device is lost or breaks in future.