The efficiency of perovskite solar cells (PSCs) has progressed rapidly, exceeding 26% for single-junction devices and surpassing 34% in perovskite-silicon tandem configurations, establishing PSCs as a promising alternative to traditional photovoltaic technologies. However, their commercialization is constrained by significant stability challenges in outdoor environments. This review critically examines key cell-level issues affecting the long-term performance and reliability of PSCs, focusing on instabilities arising from the intrinsic phases of the perovskite absorber and external stress factors. Mitigation strategies to enhance stability are discussed, alongside recent advancements in charge transport layers, electrodes, and interfaces aimed at reducing environmental degradation and improving energy level alignment for efficient charge extraction. The importance of accelerated aging tests and the establishment of standardized protocols is underscored for accurately predicting device lifetimes and identifying failure mechanisms, thereby ensuring stability under real-world conditions. Furthermore, a comprehensive techno-economic analysis evaluates how advancements in materials and strategic innovations influence efficiency, durability, and cost, which are critical for the commercial adoption of PSCs. This review delineates the essential steps required to transition PSC technology from laboratory-scale research to widespread commercialization within the global photovoltaic industry.