Is your PDF actually print-ready?
Catch PDF/X, resolution, geometry, and ink problems before the press. A property a PDF can't determine is reported not evaluable — never an invented pass.
PDF/X conformance
X-1a / X-3 / X-4 — output intent present, no disallowed RGB or live transparency for the target, version claim vs actual.
Image resolution
Effective DPI of every placed raster (after scaling) against your minimum — the #1 cause of reprints.
Bleed & geometry
MediaBox / TrimBox / BleedBox presence and bleed at or above your profile minimum; box nesting/consistency is verified for PDF/X targets (on other profiles, missing trim geometry is reported not-evaluable).
Font embedding
Every font embedded (base-14 referenced by name is flagged) so nothing reflows on the RIP.
Colour & ink
CMYK / spot inventory, RGB-in-a-CMYK-target flagging, and total-area-coverage over your maximum.
Pin a profile (PDFX-1A, COMMERCIAL-SHEETFED, …) so results are reproducible and audit-stamped with the exact rule version. This is checker evidence for your prepress hand-off, not a guarantee of press behaviour.