Open Settings Look for Backup. Might be under google/google account//system etc. Make sure Google account is selected, and it's backing up categories of info
Do I need to have a backup? Throw your computer/electronic device out the window, and then ask yourself do you want to get access to anything that was once on your device. If you say "OMG, I need xyz back!", then you need to have a backup solution. ...
Use this to visualize how accounts work in an iOS device and syncing multiple data types with multiple accounts https://docs.google.com/drawings/d/1KD9J0GzJ9k1t9auXa0kXn7y9HdQFyCEE-PXsctGfFCM/