When a subscription business decides to "fix dunning," the first meeting is almost always about email copy. Subject lines get workshopped. Somebody reads a competitor's reminder sequence aloud. This is understandable — copy is the visible part — and it is also why so many dunning improvements disappoint. The emails sit at the end of a pipeline of decisions made elsewhere: how failures are classified, when attempts fire, what the subscriber sees in the product, and how success is counted. Manage the pipeline and the copy mostly writes itself. Manage only the copy and you have decorated a leak.

The pipeline, in the order failures experience it

A failed renewal passes through five stations. Classification: what kind of failure is this — transient, credential, authentication, terminal? Scheduling: given that class, when are attempts worth making, and how many? Subscriber contact: does this class need a human in the loop, and if so, at what point in the schedule?…