Workbench will be used to track the daily limits of a salesforce org.
1. Logged into the organization where you want to verify your limits.
2. Open workbench. URL: https://workbench.developerforce.com
3. Accept any OAuth prompts to complete authentication
4. Go to REST Explorer.
5. From the options presented select: /services/data/v47.0/limits
6. Click Execute.
7. All limits for the logged-in org will be listed. Eg. single email