["The Manchester School, EarlyView. ", "\nABSTRACT\nThis study revisits the Keynes–Kuznets puzzle by examining not only whether the consumption–income ratio is mean‐reverting, but also the speed of adjustment. The Seemingly Unrelated Regression Augmented Dickey–Fuller (SURADF) panel unit root framework, combined with half‐life estimates, is employed to analyze the dynamic properties of the average propensity to consume for 110 countries from 1960 to 2019. The empirical results based on the half‐life indicate that the consumption–income ratio is mean‐reverting and converges in the long run, consistent with Kuznets' observations; however, adjustment speeds differ significantly across countries. By incorporating half‐life measures, we uncover substantial cross‐country heterogeneity, suggesting that the empirical relevance of competing consumption theories depends on the adjustment horizon. This perspective helps reconcile the Keynes–Kuznets puzzle by distinguishing long‐run equilibrium behavior from short‐run dynamics. Differences in adjustment speeds may reflect the underlying structural and cyclical forces, analogous to Schumpeter's classification of economic cycles. Methodologically, the findings underscore the value of half‐life measures beyond standard unit root tests. From a policy standpoint, these results further suggest that heterogeneity in adjustment speeds should be considered when designing consumption stabilization policies, particularly in economies facing the middle‐income trap, while also facilitating catch‐up growth in low‐income countries.\n"]