Your mobile stores sensitive data and you should take a moment to ensure you are protecting that data. Nothing complicated, just a quick review and maybe a settings change to enable encryption. Sooner or later you will upgrade when your old one is lost, stolen, or becomes too slow.
Enable automatic screen locking
Firstly, set a password/passcode or PIN to unlock your handset if you have not done so already. Even with phones that support fingerprint or facial recognition, you can set a password to require when switching them on or changing security settings.
Enable device encryption
Next, enable encryption on your handset. All modern smartphones support this.
To check whether your Android handset is encrypted touch Settings > Security & location > Encryption & credentials and look for the message “Phone encrypted”. If you do not see this go ahead and enable it on that same screen. This could take a little while if you have a lot of data stored.
To check whether your iOS handset is encrypted touch Settings > Touch ID & Passcode and scroll down to look for the message “Data protection is enabled” This is enabled by default once you set a passcode.