Monorepos, which consolidate multiple projects into a single repository, offer benefits like streamlined code sharing and collaboration but can lead to complexity and slow CI processes due to the tendency to build and test unrelated parts of the codebase. The article discusses how these challenges can be mitigated by implementing clear semantic boundaries around components, which allows for isolated testing and maintenance, thereby reducing complexity. The Buildkite Monorepo plugin provides a solution by enabling CI pipelines to run only relevant tasks based on file or folder changes, optimizing build times and improving developer productivity. This approach ensures that changes in one service do not unnecessarily trigger builds in unrelated services, which can be achieved by mapping component boundaries in pipeline definitions. While monorepos can become unwieldy, using tools like Buildkite Pipelines can help maintain fast feedback loops and efficient CI/CD processes, making it easier for teams to manage complex codebases with tight integration.