What the waterfall is telling you
Each row is a request: start time, duration, size, and type (document, script, stylesheet, font, image, XHR). The longest bars after first paint are usually your LCP and INP villains.
Third-party tags love to look small in a marketing slide and enormous on a mid-range phone. Sort by duration, not by brand name.
A practical triage order
1. Document / HTML TTFB — if the HTML is late, nothing else matters yet.
2. Render-blocking CSS and fonts — especially late @font-face without font-display.
3. Hero image or LCP candidate — wrong format, no dimensions, lazy-loaded by mistake.
4. Analytics / chat / A/B scripts that compete on the main thread.
How AuditHQ uses it
Website audits attach a load waterfall when network data is available, then suggest fixes for the slowest rows. Pair it with scheduled runs so a new tag does not silently add 800ms next Tuesday.