What Should Trigger an Email—and What Should Stop It?

An automation can be perfectly written and still annoy customers if it sends at the wrong moment. Before writing copy, make the workflow explainable as a decision tree.

Entry: Which event starts the flow? Eligibility: Which people can enter, and who is excluded? Delay: How long should the system wait, and why? Frequency: How many messages can the person receive across all active flows? Exit: Which event ends the flow immediately? Put these rules on one page. If a condition depends on data you do not reliably have, do not use it as a silent gate. For a hypothetical abandoned-cart flow, the entry is a cart created without a completed order after a reasonable window. Eligibility may exclude someone who already purchased, opted out of marketing, or is in a conflicting flow. The exit is purchase or another defined resolution. If the order event arrives late, the system needs a final check before sending. These are design questions, not a recommendation for a universal cart-email schedule.

Use test records to walk through at least these cases: a person buys before the first email; a person opts out midway; the same event fires twice; a person enters two flows at once; a key field is blank; a delayed event changes the decision; a timezone moves the send into an odd hour. Record expected and actual behavior. A workflow is ready only when it handles these cases correctly—not merely when a preview email looks good. If the flow uses commercial email, make sure opt-outs are honored. The FTC’s CAN-SPAM guidance sets U.S. requirements; mailbox providers can have additional sender rules, so read Google’s sender guidelines and Yahoo’s sender practices before launch.

Decide who can pause a flow, what signal would make them do it, and how the team will find affected contacts. If complaints spike or a purchase exit fails, pause first and diagnose. Our Journey Map gives the purpose of each flow; List Health explains the signals that tell you the program is becoming unwelcome. Try it today: Write one entry rule and one exit rule for your most important automation. Can a colleague test both?