Developers must consider the diverse range of devices and internet speeds available to users when creating applications, emphasizing the importance of frontend performance optimization. Since frontend-related code and assets account for 80-90% of user response time, reducing JavaScript bundle sizes is crucial for improving load times. The text explores the evolution of JavaScript bundles, highlighting the transition from simple script tags to advanced bundling techniques using tools like Webpack, which compiles JavaScript files into a single bundle to reduce HTTP requests and improve performance. The article discusses strategies such as running Webpack in production mode and replacing heavier libraries with lighter alternatives, like Preact instead of React, to minimize bundle size. By implementing these optimizations, the sample project reduced its bundle size from 970KB to 23KB, illustrating the potential impact of careful frontend performance tuning.