Core Viewpoint - The practice of limiting the iPhone 15 Pro Max's charging to 80% to extend battery lifespan is deemed counterproductive, as the marginal health benefits do not justify the significant reduction in daily usability [1][6]. Charging Strategy and Battery Performance - The author conducted a personal experiment over 18 months, strictly adhering to the 80% charging limit, which initially seemed to maintain acceptable battery performance [2][3]. - After 355 charging cycles, the battery capacity dropped to 91%, and the impact of the charging limit combined with natural battery degradation became noticeable, leading to increased anxiety about battery life [3][4]. - By the 17th month, with 501 charging cycles, the battery capacity fell to 89%, resulting in poor performance where the battery would deplete to near 20% by mid-afternoon, necessitating the use of a power bank [4][6]. Comparison with Other Devices - A colleague's iPhone, which did not have the 80% limit, maintained a higher battery capacity of 96% after 308 cycles, suggesting that the charging limit may not provide significant health benefits [6][8]. - Another test on the iPhone 16 Pro Max showed a battery capacity of 94% after one year with the same 80% limit, further questioning the effectiveness of this charging strategy [6][8]. Conclusion on Charging Limit - The overall conclusion drawn from the tests indicates that enabling the 80% charging limit is not worthwhile within a 1-2 year usage period, as the inconvenience of reduced battery life outweighs the minimal protective effects on battery health [6][8].