A new problem appears and someone asks for a headcount. The request goes through budget, interviews, and notice period while the problem waits. You pick the model from the type of problem.
Full-time for work that returns every day
Maintenance on a product that keeps evolving, on-call duty, a roadmap that moves every week: for work that recurs daily you need someone inside, with context that accumulates month over month. Sensitive knowledge belongs in the same list: regulated data, financial security, core intellectual property. That context lives inside the organization.
Consulting for the problem with a deadline
Infrastructure migration, performance diagnosis, architecture for a new product, technical audit: projects with a start, a middle, and an end. When the matter lasts three months, you hire a specialist for six weeks and move on.
Missing internal expertise follows the same logic: you bring in the specialist who solved it before, for six weeks.
The hybrid team
An internal Staff Engineer or CTO sets direction and priority, and a specialist consultant runs the project against its deadline. The internal person carries organizational context; the external one arrives with depth ready and leaves the team trained.
Closed cost of each model
From the ranges I have seen in the Brazilian market, a full-time Staff Engineer costs between R$ 25,000 and R$ 45,000 a month with salary, taxes, benefits, and equipment. A four-to-eight-week consulting project closes between R$ 15,000 and R$ 30,000. For a point problem the project costs a fraction of a year of hiring, and the role still goes through search, interviews, and a notice period before it produces work.
How to pick the consultant
Ask for a reference from a similar project: which problem he solved, and what still runs after he left. Then ask the process: how he diagnoses, how he delivers, how he hands knowledge to the internal team.
Alan Weiss teaches consultants to close scope by outcome in The Consulting Bible (Wiley, 2011), with a deliverable and a date written before day one.
The right consultant hands over a solved problem and an internal team that can maintain it. You know it worked when he disappears from Slack and nothing breaks.
