Dual antiplatelet therapy (DAPT), combining aspirin with a P2Y inhibitor, remains central to secondary prevention after acute coronary syndrome and percutaneous coronary intervention. However, substantial interindividual variability in antiplatelet response, particularly clopidogrel resistance associated with CYP2C19 polymorphisms, has challenged the conventional "one-size-fits-all" approach and increased interest in precision-guided antiplatelet strategies. This narrative review synthesized literature identified through PubMed, Scopus, Web of Science, and Google Scholar, focusing on randomized trials, genotype-guided studies, platelet function testing (PFT), meta-analyses, guideline statements, and emerging artificial intelligence (AI)-based prediction models. Evidence suggests that genotype-guided therapy, PFT-guided treatment, and individualized DAPT duration may improve the balance between ischemic protection and bleeding risk in selected high-risk populations. However, routine implementation remains limited by inconsistent clinical outcome benefits, heterogeneous testing strategies, modest risk-score performance, cost, infrastructure barriers, and variable guideline recommendations. Precision-guided DAPT is promising, but broader adoption requires stronger prospective evidence, standardized testing pathways, and real-world validation.