To benefit from all of the Health Report features, we strongly recommend to activate at least, on a given environment:
The Health Report generates an overview of your application's performance over 7 days. It compares it with the previous 7 days period.
Therefore, to generate a thorough Health Report, Blackfire Builds and Monitoring should run on a given environment for a period of at least 14 days.
Some advanced metrics are compiled over 6 weeks of data collection.