SiteVitals scans your live pages from the outside, so there is no plugin, agent or monitoring script to install. The first scan gives you a baseline; later scans let you see whether a protection has disappeared, a new risk has appeared or exposed software information has changed.
That matters because many of these issues are regressions. A header can disappear after a configuration change. A plugin can expose information that was previously hidden. A third-party dependency can alter without anybody changing your own code.
Findings are scored and explained in the report so you can decide what actually needs attention, rather than treating every technical observation as an emergency.