There are several ways to know if people are using TeamMood on a regular basis.
Usage overview over a selected period of time
From your Analytics view, take a look at the Usage Chart to check if people are using TeamMood in a regular basis:
It shows the number of users who used TeamMood regularly, the ones who used at least once during the selected period, and the ones who did not used it.
This information is also shown in the Reporting view thanks to the Distribution pie chart in the Participation section:
Weekly participation rate
You can get an export of the weekly participation rate for a team from your Export Center.
Each line is the participation rate for a week, from the beginning of TeamMood usage:
You'll get an overview of the usage trends from your Periodic Digests that you get by email or Slack etc.
Also find these trends in the Reporting indicators.