9 Dec 2025

Frequency caps that protect trust

A cadence cap that product can bypass with a checkbox labelled “one-off” is not a cap. It is a suggestion with a trapdoor. In class we make learners count how many one-offs shipped last quarter. The number is usually high enough to end the argument about whether the trapdoor exists.

The studio rewrite is an exception form: who asked, which message family, which window is being broken, when it reverts, who tells support. It is mildly hated in week seven and quoted in week twelve. That arc is familiar.

Caps should sit per person per family per rolling seven days, not per campaign name. Campaign names get reinvented to dodge the number. People do not. If your warehouse cannot join identity across app and email yet, write the cap on the channel you can see and list the gap as a limitation. Do not invent a unified number.

Trust, in this narrower sense, is the absence of a surprise ping after someone already completed the task. We have watched password-reset traffic stay clean while “complete your profile” mail arrived four times in a weekend. The second family needed a cap of one, not a prettier subject line.

Send-Window Architecture ends with a monthly ritual that reviews caps the way finance reviews expenses. If nobody attends, the cap will rot. We would rather you know that than leave with a diagram that looks finished.