How to write a brief that works across multiple topics

A brief that only works for one topic defeats the point of writing it once. The usual mistake is putting topic-specific detail (a particular feature, a particular campaign angle) into the brief itself, which forces you to rewrite it every time.

Keep the brief scoped to what doesn't change: the product, the audience, and the tone. Save feature-specific or campaign-specific detail for the topic stage instead, where it belongs. A good test: if a detail would need to change for next week's topic, it probably shouldn't be in the brief.