The fastest way to protect a studio is to turn down the work that would have drained it.
Not every brief is a fit, and pretending otherwise helps nobody. A project where design is not the real problem will not be fixed by better design.
So we say no early, on the first call, while it still costs nothing. Usually we can point somewhere better: a positioning consultant, a developer, occasionally just a clearer conversation with their own team.
Saying no is not precious. It is the only way the yes means anything, because it is what keeps the calendar honest.
The clients we do take on get a studio that is not quietly resenting three other projects.