Cross-platform strategy can differ across features and teams within a company. For Math and Chess at Duolingo, we mix KMP, web runtimes, and more. We'll share a decision framework of when and why to choose each cross-platform approach, considering Android project porting and building LLM-integrated features for rapid iteration. We'll also discuss navigating realistic scenarios where features are not built multi-platform, and we propose processes for streamlining development in those scenarios.