Fragmentation testing is crucial in ensuring compatibility across various devices, operating systems, and browsers. With over 63,000 possible browser-platform-device combinations, it's essential to identify the right devices for testing. A framework that considers global trends in mobile usage, device popularity, and BrowserStack data can help determine the minimum number of devices needed for maximum market coverage. For a small website with less than 15,000 unique visitors per month, testing on six specific devices covers 93% of the iOS market, 76% of Android, and 44% of all screen sizes, potentially preventing late-night emergencies due to compatibility issues.