How to choose a mobile device for testing, what will you focus on?

When choosing a mobile device for testing, I consider the following criteria:

• Target Audience: Which devices and OS are most popular among the application's users.
• Operating System and Version: Coverage of current Android and iOS versions, as well as support for outdated ones if important.
• Manufacturer and Model: Different manufacturers may have specific features in their OS and hardware.
• Screen and Resolution: To test interface responsiveness.
• Technical Specifications: Performance, memory capacity, presence of specific sensors or features.
• Device Availability: Physical access or remote access possibilities.

For example, if the application targets a mass market, it is advisable to select popular models with different OS versions to cover the maximum number of users.