The last heuristic is to avoid a single team responsible for two complicated domains. This might seem feasible with a larger team of eight or nine people, but in practice, the team will behave as two subteams (one for each domain), yet everyone will be expected to know about both domains, which increases cognitive load and cost of coordination. Instead, it’s best to split the team into two separate teams of five people (by recruiting one or two more team members), so they can each be more focused and autonomous.
