Most value a customer adds after day 30 arrives after day 90. Count what your flows send then.
List your flows with their delay in days. Most of the list sits inside the first month: welcome, abandonment, post-purchase, a cross-sell near day 30. After that comes a gap, then a winback somewhere past day 90. That calendar follows the odds of a second order, which peak in the first weeks. It misses where the money lands.
In the skincare file (measured), about two-thirds of the change in value per customer between day 30 and day 365 happened after day 90. A flow list that goes quiet after the first month has nothing scheduled for that stretch.
The two facts fit together. A second order, when it comes, tends to come early. Value arrives later, because the customers who stay go on to place third and fourth orders over the following months. So value keeps arriving after the flows stop, and a late touch reaches fewer people with more money riding on each one.
In accounts I've audited, the direction holds across categories even when the timing moves. In seasonal apparel, the back half of the curve sits in a season that hasn't started yet.
Take your last full-year cohort: customers whose first order falls in a twelve-month window that ended at least a year ago. Every one of them has had a full year to buy. For each order, count the days since that customer's first order, which is day 0. Bucket the orders into 30-day windows and add up net revenue in each, after refunds.
Divide cumulative revenue by the number of customers you started with, including the ones who never came back. That gives revenue per acquired customer. Chart that curve, because it carries order value and frequency together. A repeat-rate curve counts returns and ignores what each one was worth, so it can't show you where the money arrives.
The halfway day is the day cumulative revenue per acquired customer reaches the midpoint between its day-30 and day-365 values. Take an invented curve: $42 at day 30, $118 at day 365. The rise is $76, so the halfway mark is $80. If the curve crosses $80 at day 140, everything sent before day 140 competes for the first half of that rise.
The second half goes to whatever is still sending something worth opening in month five or six. In a flow list built around the first month, that slot is empty. Customers keep buying through it, and the program has nothing on the calendar to meet them. In the skincare file, the halfway day falls after day 90, because only about a third of the rise had arrived by then.
Go back to the flow list. Mark every message that fires after the halfway day, and total what those messages earned last quarter. Count by message. A flow with one late email and six early ones still belongs to the first month.
If the count is short, that's the gap to fill. The natural candidates are replenishment reminders timed to the reorder gap and loyalty touches that mark a third or fourth order. They qualify because they still have something true to say months after the first order. Move one past the halfway day. Read the curve again next quarter to see whether the second half of the rise moves.
This is one chapter of The Second Order, which is free and readable in full on a single page with no form in front of it.