Legacy Maemo 5 Documentation/Human Interface Guidelines/Reality Checks
Reality Checks
This chapter provides guidance for improving usability within applications, even beyond standard testing procedures. (Other very useful information can be found in the Checklists Section of the GNOME HIG.)
Hardware Keys
Determine which hardware keys or buttons on the mobile device that is being tested might be assigned to various functions within the application. This is a good way discover whether or not certain functionality might only need hardware control rather than onscreen menus or options. For instance, most mobile devices have a hardware for volume. In this case, users are fairly comfortable with using a standardized hardware key and most likely don't need the function repeated onscreen.
Different Devices
Given the inherent differences in the selection of mobile devices on the market, it is common that certain features within an application might not always translate between devices -- some features may not work altogether. Therefore, it extremely important either test applications in as many devices as possible or allow device users to provide feedback about issues they may be experiencing.