Evaluating the performance of language models (LLMs) is a pressing issue for companies working with generative AI. Defining what makes a model "good" and measuring its performance are challenging due to the diverse range of LLM applications. Existing evaluation methods, including benchmarks and user preference comparisons, have limitations in scalability and objectivity. The future of LLM evaluation lies in scaling testing with machine learning systems, such as reward models that capture user preferences, and simulating user sessions to generate comprehensive test cases. These approaches will help developers select models, create effective prompts, ensure compliance, and enhance LLM quality.