A client came to us wanting two mobile engineers. We asked what the app was doing badly: screens felt slow, they said. The traces showed one screen making nine calls, three of them for the same user object. They didn't need mobile hands, they needed someone to own the API contract. So now we ask to see one real screen's network trace before we scope a role. It costs an hour, and it has changed the ask twice.
Worth knowing what the last role you hired turned out to actually be.