Customer Lifetime Value by Channel: Why the Cheapest Sale Isn't Always the Most Valuable

In an earlier post we looked at true profit per channel — what you actually keep from a single order once fees, ads, and fulfillment come out. That number is essential, but it quietly assumes every customer is a one-time event. Most aren't. The moment you zoom out from a single order to the whole relationship, the ranking of your channels can flip.

This is the follow-up we promised: how to measure customer lifetime value (LTV) across Amazon and DTC, and why the channel with the thinner per-order margin sometimes wins over time.

Why per-order profit tells only half the story

Per-order profit answers "what did I make on this sale?" LTV answers a bigger question: "what is this customer worth to me over their entire relationship with my brand?"

Those are very different numbers, because customers don't buy once. A shopper who returns three times at a modest margin can be worth far more than a shopper who buys once at a great margin and never comes back. If you only optimize per-order profit, you'll systematically over-invest in channels that produce cheap one-time buyers and under-invest in channels that produce loyal repeat buyers.

The rule of thumb: per-order profit tells you which sales are efficient. LTV tells you which customers are valuable. You need both.

A simple way to calculate LTV

You don't need a data science team. A workable LTV estimate needs just three inputs, measured per channel:

• Average order value (AOV) — the typical revenue per order on that channel.
• Contribution margin % — the share of that order you keep after variable costs (fees, ads, shipping, cost of goods).
• Purchases per customer — how many times an average customer buys from you on that channel over a defined window (say, 12 or 24 months).

Multiply them:

LTV = AOV × Contribution Margin % × Purchases per Customer

A quick example. Suppose a customer's typical order is $40:

• Amazon: $40 AOV × 22% margin × 1.3 purchases = ~$11.40 LTV
• DTC: $40 AOV × 38% margin × 2.4 purchases = ~$36.50 LTV

Same product, same price — but the DTC customer is worth roughly three times more over their lifetime. Part of that is the higher margin (no marketplace referral fee), and part of it is the higher repeat rate. Neither shows up if you only look at a single order.

The two levers that actually move LTV

Notice that in the example above, the AOV was identical. All the difference came from two places.

1. Contribution margin

This is where channel economics live. Amazon takes a referral fee (often ~15%), and if you use FBA, fulfillment and storage on top. DTC avoids the marketplace cut but trades it for payment processing, shipping you now pay for directly, and customer acquisition cost. The net margin is usually higher on DTC — but not always, and that's exactly why you measure it per channel instead of assuming.

2. Repeat purchase rate

This is the quiet giant. A channel where customers come back is compounding; a channel where they don't is a treadmill.

• On Amazon, the customer is largely Amazon's. You rarely get their email, you can't easily market to them again, and they'll happily buy a competitor next time. Repeat rates tend to be lower unless you're winning Subscribe & Save.
• On DTC, you own the relationship — email, retargeting, loyalty programs, subscriptions. That ownership is the entire reason DTC repeat rates (and therefore LTV) tend to run higher.

If your two channels have similar per-order profit, repeat rate is usually what breaks the tie.

Bring CAC into the picture: the LTV:CAC ratio

LTV on its own can mislead you, because a valuable customer you paid too much to acquire is still a bad trade. Pair LTV with customer acquisition cost (CAC):

LTV:CAC ratio = Lifetime Value ÷ Cost to Acquire That Customer

A common benchmark is a 3:1 ratio — you want to earn about three dollars of lifetime value for every dollar spent acquiring the customer. Below ~1:1 you're losing money on every customer; far above 3:1 you may actually be under-investing and leaving growth on the table.

This reframes the channel debate nicely:

• Amazon often has lower CAC (built-in demand, high purchase intent) but lower LTV (you don't own the customer).
• DTC often has higher CAC (you pay for the traffic) but higher LTV (you keep the relationship).

The winning channel is the one with the healthier ratio, not the bigger single number — and that can differ by product, price point, and category.

What this changes about how you invest

Once you're looking at LTV and LTV:CAC by channel instead of per-order profit alone, a few decisions get clearer:

• Where to spend the next marketing dollar. Put it into the channel with the stronger LTV:CAC ratio, not just the cheaper click.
• Whether to chase Amazon volume or DTC loyalty. Amazon is often the better discovery engine; DTC is often the better retention engine. Many brands use Amazon to acquire and DTC to keep.
• Which customers to try to migrate. If DTC LTV dwarfs Amazon LTV, inserts and post-purchase nudges that move buyers into your owned channel can be worth more than any single ad campaign.
• When a "worse" channel is actually fine. A thinner-margin channel with a great repeat rate can quietly be your most valuable one.

The honest caveats

Two things worth saying plainly, because LTV math is easy to fool yourself with:

1. Your numbers are estimates, not gospel. Repeat rate especially is hard to measure on Amazon, where you often can't tie orders back to a single customer. Treat LTV as a directional signal for where to lean, not a precise forecast.
2. LTV changes over time. Prices shift, fees rise, ad costs climb, repeat behavior moves. Recompute it periodically rather than deciding once and forgetting.

The bottom line

Per-order profit tells you which sales are efficient. Lifetime value tells you which customers — and which channels — are actually building your business. When you measure AOV, margin, and repeat rate per channel, then weigh it all against acquisition cost, the "cheapest" sale often stops looking like the most valuable one. That shift in perspective is usually the difference between chasing volume and building a brand that compounds.