Reticulated platelets, young and newly released from the bone marrow, represent a critical link between thrombopoiesis and platelet function. These larger, RNA-rich platelets are increasingly recognized as biomarkers of megakaryocyte activity and bone marrow output, offering insights into the dynamics of platelet production. This review explores the biology, measurement, and clinical significance of reticulated platelets in both health and disease. We discuss their role as diagnostic and prognostic markers in conditions such as thrombocytopenia, immune-mediated platelet disorders, and myeloproliferative diseases. Furthermore, the article highlights emerging evidence on their utility in monitoring bone marrow recovery, assessing platelet turnover, and predicting treatment responses, particularly in immune thrombocytopenic purpura and chemotherapy-induced thrombocytopenia. Advances in flow cytometry and RNA detection techniques have enhanced our ability to quantify and study reticulated platelets, paving the way for their application in precision medicine. By serving as a window into thrombopoiesis and platelet kinetics, reticulated platelets hold promise for improving the diagnosis and management of hematologic disorders.