Acute respiratory distress syndrome (ARDS) is characterized by heterogeneous alveolar collapse and refractory hypoxemia, posing significant challenges to the optimization of mechanical ventilation strategies. Given the substantial inter-patient variability in lung recruitability, optimal approaches for lung recruitment maneuvers (RMs) and positive end-expiratory pressure (PEEP) settings remain controversial. The recruitment-to-inflation ratio (R/I), a recently proposed bedside assessment tool, quantifies alveolar recruitability by analyzing changes in respiratory system compliance across different PEEP levels, thereby providing a basis for individualized ventilation strategies. R/I is simple to perform, requires no additional equipment, and can be repeatedly measured at the bedside to dynamically track treatment responses. Multiple studies have demonstrated good agreement between R/I and recruitability assessed by computed tomography, electrical impedance tomography, and lung ultrasound. However, the current evidence is predominantly derived from small-sample, single-center studies. Measurement discrepancies across different ventilator models may compromise the accuracy of R/I, and no universally accepted threshold for distinguishing high from low recruitability has been established. Future large-scale, multicenter clinical trials are warranted to further validate the reliability of R/I and to clarify its clinical value in balancing the benefits of lung recruitment against the risk of ventilator-induced lung injury in ARDS management.