Explore a comprehensive conference talk on gradually adopting contract checking in production code. Learn about the four fundamental semantics of contract checks and how to implement them in live systems. Discover the proposed C++23 language support for contracts and practical alternatives using existing libraries. Gain insights into preconditions, postconditions, invariants, and error reporting techniques. Understand the differences between wide and narrow contracts, and how to effectively use contracts in test drivers and unit tests. Examine key issues such as expensive checks and customization options. Follow a step-by-step workflow for implementing contracts, from ignored comments to assumed optimizations, to improve code quality and catch errors early in the development process.