If you aren't using an iCloud backup you're tempting fate that you will need to restore to a super old backup. Unless you religiously plug your iPhone 8 into your computer and backup into iTunes you will at some point be without a current backup when you need it.
That's why I recommend using iCloud to backup your iPhone. The catch here is that you need to make sure sure you buy more than the 5GB of storage Apple gives you with your account. It's annoying, but it's better than remembering to plug in every day. Now that you can share iCloud storage with your family, it's also cheaper.
Go to Settings -> iCloud -> iCloud Backup -> On and then let it complete the backup. This first backup will take a while and you should be plugged in and on WiFi, but each subsequent backup will go much faster.