GitHub's evolution in its on-call strategy, driven by its growing product complexity and size, highlights a shift from a monolithic on-call system to a more decentralized model where each engineering team is responsible for the code they maintain. This change aimed to address the inefficiencies and challenges of the previous system, such as engineers' unfamiliarity with the vast monolithic codebase and imbalance in on-call responsibilities. The transition faced logistical hurdles like file ownership and monitoring, as well as cultural challenges, including adjusting to remote work during the pandemic, training engineers new to on-call duties, and fostering a supportive, blameless culture. GitHub implemented a new service ownership model, tailored monitoring, and a focus on work-life balance, while promoting long-term improvements in operational practices. The initiative led to improved incident resolution times, but GitHub continues to seek feedback and refine its processes to ensure sustained operational excellence and support for its engineering teams.