Session-based testing can offer benefits when formal requirements are not present, incomplete, or changing rapidly.
According to Jon Bach, one of the co-founders of the methodology, the mission explains "what we are testing or what problems we are looking for.
Often charters are created from a specification, test plan, or by examining results from previous sessions.
The tester creates and executes tests based on ideas, heuristics or whatever frameworks to guide them and records their progress.
This allows reporting on the number of sessions per area or a breakdown of time spent on testing, bug investigation, and setup / other activities.