Should you spend on ads or on retention?

Compare cost per new customer against cost per repeat order. If the first is more than three times the second — and it usually is — the next unit of budget belongs in retention.

Why the answer is what it is

This is not an argument against advertising. It is an argument for advertising into a business that holds onto people, because acquisition into a store nobody returns to is a subscription to a treadmill.

What this looks like in practice

Traffic is the expensive problem and conversion is the cheap one. Doubling a 1% conversion rate is usually easier than doubling visitors, and costs nothing per month.

Retention beats acquisition on every measure, and almost every store spends the other way round.

The slowest part of most mobile stores is images nobody resized. It is the most common performance problem and the easiest to fix.

Where a mobile app comes into it

Push notifications are the one growth channel you do not rent. Every other route to a customer is paid for again each time.