Most React Native developers test on flagship devices with fast WiFi — but most of the world's users are on budget Android phones with variable connectivity and tight data budgets. Shipping a production app in India forced me to rethink every assumption about performance, bundle size, and UX. The solutions didn't just fix my app for constrained users — they made it better for everyone. A practical blueprint for building React Native apps that are faster, leaner, and more resilient — whether your users are in Mumbai, Manila, or Munich.