Choosing mobile devices for testing can be overwhelming due to the vast number of options available. To ensure comprehensive testing coverage, it's essential to consider best practices such as selecting devices based on target users and region, choosing a mix of high-end and low-end models, and periodically reassessing device selection. Manual testing should focus on user experience-related issues, while automated testing can be used for efficiency and cost-effectiveness. A balanced approach that incorporates both manual and automated tests is recommended. Recommended mobile devices vary by company size, region, and market share, with the latest Pixel and iPhone models being popular choices. By considering these factors and selecting the right number and type of devices, organizations can ensure optimal coverage, efficiency, and cost-effectiveness in their mobile app testing strategies.