It is now more than twenty-five years since ‘reasonable care’ became the ubiquitous benchmark of importer conduct under US customs law. This article explores the impact of the reasonable care standard on US importers since its inception in 1993 as part of the ‘Customs Modernization Act’. The statutory and regulatory basis for reasonable care is examined, as is the evolution of the relationship under reasonable care between US Customs and Border Protection (CBP) and importers. The closely related effects of the companion tenets of reasonable care introduced by CBP – ‘shared responsibility’ and ‘informed compliance’ – are also discussed. This article then examines with specificity recent section 592 caselaw from the US Court of International Trade and the Court of Appeals for the Federal Circuit that has clarified the scope and meaning of reasonable care. Also addressed are troubling developments, separate from but closely tied to reasonable care, concerning the expansion of personal liability under section 592 found in the recently promulgated judicial standard regarding the ‘introduction’ of goods into the United States.