Knowing this value across the estate helps to gauge the user experience and how much time is being spent waiting for the offline phases to complete. One stat I gather is the offline time for the upgrade, ie the time between when the downlevel (online) phase is completed and the computer is restarted and the time when the offline phases have completed and the OS is brought back to the logon screen again. These stats can be useful for identifying areas of potential improvement in the upgrade process. For my Windows 10 feature update installation process, I like to gather lots of statistics around the upgrade itself as well as the devices they are running on so we can later report on these.
