Successful navigation of real-life environment requires flexible titration of effort based on the possible rewards. Here, we investigate how the flexibility of effort allocation develops throughout adolescence by studying the neural underpinnings of reward-maximizing strategies during a value-guided action. Our main hypothesis is that when faced with an environment with varying rewards and their expectancy, adolescents will use qualitatively different strategies to overcome the cognitive immaturity. Alternatively, adolescents may use an adult-like strategy, but in a lesser degree. Using EEG with a novel analytic technique that separately quantifies motor preparation and execution efforts from the ERP component lateralized readiness potential (LRP), we demonstrate evidence for our main hypothesis. When responding to an unexpected target, adults (21 years and above) showed a greater executional effort for a large than small reward. Such a pattern was somewhat reversed in pre-adolescents' (10-13 years). Meanwhile, adolescents (14-20 years) allocated motor efforts more equally regardless of the reward levels and their expectancy. These manifested differences represent distinct reward-maximizing strategies across development that are shaped by cognitive maturity, which reflects an individual's endeavor to maximize adaptive fit in the dynamics of real-life environment.