Use when the question is whether email will reach the inbox, covering sending domain setup, authentication, list hygiene, complaint and bounce rates, or a drop in delivery.
Use when turning existing copy, a blog post, an announcement, or a brief into an email that works in an inbox, including deciding what to cut and what to link out to.
Use when planning or restructuring what pages a site has and how they connect: hierarchy, navigation, URL patterns, breadcrumbs, and internal linking. Not for XML sitemaps, which are in seo-audit.