Monorepos, a popular architectural pattern for storing all application code in a single repository, offer several benefits but also present unique scaling challenges as they grow. These challenges include managing increased developer contributions, coordinating sequential database schema changes, and dealing with longer build times due to increased code and tests. Common solutions include using commercial or custom tools for schema management and implementing strategies like merge queues or release trains to handle build and merge operations efficiently. However, as monorepos reach their scalability limits, splitting them into smaller, logically separated repositories can provide relief. This approach helps maintain efficiency and manageability without necessarily doubling the workload, as the familiarity with existing tools and workflows remains. Measurement of both qualitative and quantitative metrics is crucial to identify pain points and improve processes, ensuring developer satisfaction and efficient CI pipeline performance. Buildkite is highlighted as a tool that offers flexible solutions for scaling monorepo CI pipelines, allowing users to tailor their workflows to their specific needs while keeping source code secure.