Coverage across hardware.
WHY EMULATORS ARE INSUFFICIENT
They do not reproduce performance, battery consumption, touch behaviour, camera and sensor behaviour, or real network conditions.
WHAT DEVICES TO OWN
A modest Android device, representative of your actual users A current Android device An iOS device, if targeting it Ideally, an older iOS device
WHY THE MODEST ONE MATTERS MOST
It reveals every performance problem the others conceal.
WHAT DEVICE FARMS PROVIDE
Access to many devices remotely, for automated and manual testing.
WHAT THEY SUIT
Verifying across manufacturers and versions Reproducing a crash reported on a device you lack
WHAT THEY DO NOT REPLACE
Holding a device and using the application as a person would.
WHAT TO PRIORITISE COVERAGE BY
Your own analytics: which devices and versions your users actually have.
WHAT TO DO BEFORE YOU HAVE ANALYTICS
Use platform distribution figures for your market.
WHAT TO TEST OUTDOORS
Contrast and legibility.
WHY
Screens are used in sunlight here routinely, and it fails differently than indoors.
