David Smith’s excellent Sleep++ app is my killer app when it comes to sleep analysis, a glaring omission from the Apple Watch. It's become second nature for me to open Sleep++ as I tuck myself in bed for the evening.
This native watchOS 2 app collects data from watch sensors to measure sleep quality and duration, which can then be reviewed in greater detail in a companion iPhone app and synced with your Health database.
The updated Sleep++ 2.0, now available as a free download in the App Store, takes sleep analysis to the next level with major improvements to its sleep analysis engine and new features such as better Health integration, an improved Night Detail view, night trimming and timezone support.