We highly recommend that you use a child theme if you have a template customizations. This allows you to make code changes that won’t be overwritten when an X update is released. Even if you have a child theme, you still have to update the parent theme because every now and then there are WordPress updates and that is why as the theme developer, we also keep up with these updates. Getting updated will prevent you from any conflicts and even site vulnerability because this is the main reason for updates.
Hope this helps.