Count the combinations
A hypothetical form with four roles, three account states, two languages, and three network conditions already has 72 combinations before individual field values are considered. Adding one feature can affect several existing paths. The practical question is which combinations expose meaningful risk.
Use interaction coverage deliberately
Combinatorial testing selects cases to cover interactions among inputs. Pairwise coverage does not guarantee detection of failures that require three or more interacting factors. See NIST’s introduction to combinatorial testing.
Add targeted scenarios
For a payment workflow, explicitly test duplicate notifications, interrupted requests, and authorization boundaries. For a multilingual form, combine long text with narrow screens and validation errors. These examples should come from your system’s behavior, not a generic checklist copied without review.
Keep a coverage map
List the dimensions, impossible combinations, high-impact cases, and gaps you accept. Separate business correctness from visual layout and performance so a passing browser screenshot is not mistaken for evidence that accounting is correct.
Try this: Map the dimensions of one workflow, choose a manageable interaction set, then add the three failures that would be most expensive to miss.