Strip the dashboards away from any retry tool and one design decision remains, the one that determines nearly all of its results: in what order, and on what evidence, does it spend a subscriber's limited attempts? Issuers watch retry behaviour. A card retried blindly six times in two days does not merely fail six times; it teaches the issuer's systems that this merchant retries blindly, and the seventh attempt — the one timed to payday, the one that would have worked — arrives carrying the reputation of the first six.

A sound sequence starts by reading before it spends. The decline code on the first failure is evidence: insufficient funds points at the calendar, a replaced credential points at the updater and the customer, a hard decline points at the exit.…