A post-purchase discount email isn't a retention strategy

A discount code sent ten days after a first purchase, sent to every customer regardless of category, product, or behaviour since, is the most common thing labelled a 'retention programme' — and it's really just one automated email.

A genuine retention system segments by actual behaviour: time since last purchase relative to the category's typical repurchase cycle, engagement with previous emails, and product category, at minimum, with different messaging and timing for each segment.

The highest-leverage segment is usually the one getting the least attention: customers approaching their expected repurchase window who haven't yet returned. A well-timed, relevant prompt here typically outperforms a generic broadcast to the full list by a wide margin.