Use unique passwords
Do not reuse the same password across smart-home and unrelated services.
Use multi-factor authentication where supported
A second factor can reduce the risk from a stolen password.
Review household access
Remove former residents or unused guest permissions.
Protect account recovery
Keep recovery email, phone and backup methods current and private.
Keep in mind. Compatibility is not permanent. Confirm the current manufacturer, platform and certification information before purchasing, resetting or migrating a device.