Let’s talk about a question that keeps many retailers up at night: Why aren’t my customers coming back?

This month, the Online CX Index, a partnership between Inside Retail and Humii, introduced one of its most important additions yet: Post-Purchase Retention. Designed to shed light on what drives repeat purchases — and what turns customers away — this new metric offers a powerful lens into what happens after the checkout, and why it matters more than ever.

Rethinking retention

“Retention isn’t just about discounts or points programs,” stresses Humii co-founder and CEO Mareile Osthus. “It’s about the full end-to-end experience, from discovery to delivery to return. The goal is to measure the likelihood of a shopper coming back, based not on historical sales, but on what they’ve actually experienced.”

At the end of every online mystery shop, Humii is asking one simple question: “Based on your experience, how likely are you to return to this retailer?” Then, Humii digs deeper into why, to understand what worked, what didn’t, and where retailers are winning or losing future sales.

“The result is a new benchmark for experience-led retention. And the good news? It’s a likelihood, not a life sentence. There’s always room to improve and to turn things around,” shares Osthus.

What the data tells us

Every mystery shop conducted by Humii assesses up to 200 data points across the full online journey, covering not just the website and purchase experience, but delivery, unboxing, returns and refunds as well as loyalty and retention. Osthus says it is often during this post-purchase phase where retention quietly breaks down.

Together, they provide a fuller view of shopper behaviour, from drop-off before checkout, to whether shoppers will come back at all.

The data reveals:

The highest retention score on the index is 96 per cent.

The lowest retention score is 55 per cent.

The average across the Online CX Index is 67 per cent.

“With customer acquisition costs continuing to climb, retention is no longer a nice-to-have, it’s essential,” says Osthus. “Retaining customers is significantly more cost-effective than constantly acquiring new ones, yet many retailers still underestimate its impact. If only 55 per cent of your first-time shoppers are likely to return, the maths is simple: You’ve already lost your CAC and any chance of meaningful lifetime value. That’s not just inefficient, it’s unsustainable.”

Spotlight on four Accent Group brands

Osthus zooms in on four brands from Accent Group that are performing well, all ranked between #19 and #48 on the Online CX Index, and explores what’s helping (or hindering) retention.

#19 – Stylerunner | Retention Score: 80 per cent

A strong performer, Stylerunner’s online journey is well-received. However, some shoppers flagged unanswered customer service emails, which, while minor, introduce risk to an otherwise polished experience. As a side note, and not particularly mentioned as a non-return reason, is the uncertainty about the benefits of the membership program. 

#27 – Platypus Shoes | Retention Score: 75 per cent

Platypus shows solid performance overall, but technical issues in the returns portal and poor communication around refunds were frequent concerns. These friction points can undermine confidence and deter repeat visits.

#40 – Skechers | Retention Score: 69 per cent

The most consistent feedback for Skechers was a lack of communication during returns. Shoppers were unsure if their items were received or refunds processed, gaps that create avoidable uncertainty and affect brand trust. In addition to this, some shoppers never received a response going through the contact form. 

#48 – Hype DC | Retention Score: 72 per cent

Post-purchase performance is above average, indicating a generally positive experience after the transaction. However, Hype DC faces considerable pre-purchase abandonment, with 28 per cent of mystery shoppers exiting the site before checkout after finding the same item at a lower price elsewhere. This highlights a clear opportunity to reassess competitive pricing strategies and strengthen value perception throughout the shopping journey. Additionally, among those unlikely to return post-purchase, a recurring issue was the lack of response via the contact form, suggesting a need to improve responsiveness in customer support touchpoints.

What really drives (or destroys) retention

Across Humii’s research, one thing is clear: Most customers don’t fail to return because they dislike the product. They don’t come back because of avoidable friction in the experience.

The most commonly cited issues? According to Humii’s CX data, these are the top five reasons shoppers are unlikely to return:

Difficult return process.

Slow delivery.

Poor delivery communication.

Product doesn’t match description.

Limited payment options.

“These are not loyalty problems,” says Osthus. “They’re operational pain points, and each one is fixable. The challenge is knowing where they exist in your journey.”

Looking ahead

Accent Group’s performance reflects strong digital foundations and high shopper sentiment. With some focused improvements, each brand can increase retention and climb further up the CX Index. 

Osthus says that as the retail calendar ramps up toward peak season, there’s never been a better time to ask if your customers are coming back, and if not, do you know why not?

“Unless you want to lose customer acquisition costs and customer lifetime value. After all, retention is a journey, not a given.”