Choosing the signals
The right signals represent investment rather than curiosity. Importing data, connecting another system, inviting colleagues, completing a core workflow, returning on several separate days, and approaching a plan limit all indicate somebody is trying to make the product part of how they work. Logins, sessions and time in app are poor signals, because a confused user and an engaged one produce similar numbers.
Setting the threshold
Choose the threshold empirically. Compare what converting accounts did in their first two weeks against what non-converting accounts did, and keep the actions where the gap is large. Then set the bar where the resulting volume matches what your team can actually follow up, because a qualification rule that produces more accounts than anyone can contact will be applied informally by whoever looks first.
Account level as well as user level
For most business products the account is the more meaningful unit. One person exploring is weak evidence. Three or four colleagues from the same organisation active in the same week implies an internal conversation has already taken place, which is one of the strongest signals available and is invisible in a user-only view.
A worked threshold example (illustrative)
An account qualifies when three conditions are met within fourteen days: at least fifty records imported, at least two active users, and one core workflow completed from start to finish. Consider three trials. The first has imported two hundred records with four users but has not completed a workflow: they have set up and not yet reached value, so the right action is a prompt about the missing step, not a sales call. The second has one user who completed a workflow with sample data: they are evaluating, and belong in nurture. The third meets all three conditions and should reach a salesperson the same day, in a conversation that references exactly what they built. The numbers are illustrative; the discipline of defining them in advance and testing them against conversion is not.