A shipment clearing customs without a hold does not mean the entry is final. Most customs authorities, including HMRC, CBP and the EU member states, retain the right to audit a past import entry for several years after release — commonly three to five years depending on jurisdiction — and can reassess duty, VAT or penalties if the audit finds a discrepancy.
The triggers that most commonly bring on a post-clearance audit are a pattern of valuation that looks inconsistent across shipments of the same goods, a tariff classification that differs from what similar importers use for comparable products, or a change in supplier or origin that is not reflected in supporting documentation.
What an audit actually checks is whether the declared value, classification and origin on the entry are supported by the underlying commercial documents — the purchase order, the supplier invoice, the payment record, and in origin disputes, evidence of where the goods were actually manufactured, not just shipped from.
The practical defense is simply retaining a complete, internally consistent document set per shipment — commercial invoice, packing list, bill of lading, and the declaration itself — for the full retention period the destination authority requires, not just until the goods clear the port.