You can set up Avaz (versions 3.2 and below) to track Avaz usage. 
For versions 4.0 and above this feature is not available; instead you can view Analytics - click here to read more - 
What kind of Analytics does Avaz provide?

To set up data logging :

Tap Settings > Track session. Set to ‘start’ to start tracking. This pops up a window and prompts you to enter the Session name and description before turning on the data logging.

Once data logging is turned on, it is indicated through the status display “tracking is on” on the top left corner, next to the Avaz logo. You can tap the status display to either pause tracking or stop tracking. When you stop tracking through Settings >Track session = ‘Stop’, it displays the logged data and prompts you to enter session notes. You can then save or email the data log.