Been building in this space and the thing that surprised me most is how much of good lifecycle email is suppression, not sending. Skip people who already did the action. Stop a sequence the moment someone converts. Exit on the event you were nudging toward. Get that wrong and you annoy your best users into unsubscribing. A few rules that have worked: Trigger off the behavior, not a calendar day. Always set an exit condition. Never send a "did you try X" email to someone who ...