What is customer retention?

Retention describes repeat business: how many customers return to the store after their first purchase and how long they stay with the brand. This is the flip side of acquisition, which is measured by the number of new customers brought in through advertising.

The math behind this concept has been well-known in ecommerce for years: acquiring a new customer can cost several times - and in extreme cases, more than twenty times - as much as the maintenance costs for someone who has already made a purchase. That’s why channels that rely on repeat business - such as email marketing, loyalty programs, or mobile apps - are evaluated differently than campaigns focused on first-time customers.

In practice, retention is also a test of whether a brand has a reason to exist beyond price. A customer returns because they get something they can’t find elsewhere, or because you recognize them and reward them for buying again. A discount given without this foundation only teaches them to wait for the next sale.