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Nobody ever came back for the subject line.
When Hai Linh Nguyen from the Flits team asked Daniel Martin of Glaze Digital what most Shopify merchants still get wrong about retention, his answer wasn't about email flows or discount codes. It was about everything that happens before the inbox gets involved.
People come back because the product is good, the packaging feels considered, and when they have a question, someone answers it the same day. The email they open two weeks later just reminds them of all that. Takes them ten seconds to click through and buy again.
That's retention. Most Shopify brands are building half of it.
The average post-purchase experience goes: confirmation email, shipping update, silence. Then, somewhere between two and four weeks later, a Klaviyo flow fires. By that point, the customer has already made their mind up. The email didn't decide that. The silence between dispatch and follow-up did.
The brands with strong returning customer rates treat the post-purchase window as the product itself. Every touchpoint between the order confirmation and the next visit is a marketing moment. The inbox just amplifies whatever they built there.
Enter Glaze Digital
That's the argument Glaze Digital has been making with its clients, and the results back it up.
The Belfast-based Shopify Plus agency has built over 250 stores since 2014, sits in the top 1.5% of Shopify's global partner network, and its clients turn over more than £20 million a month. They work across DTC and B2B, drinks brands and fitness equipment and wholesale beauty, which means Daniel has seen retention fail in more contexts than most people have seen it work.
Linh from the Flits team sat down with Daniel Martin, Customer Success Manager at Glaze Digital, as part of the Flits Agency Interview Series. Here's that conversation.
1. What’s one thing you wish more Shopify merchants understood about keeping customers coming back in 2026?
“That retention isn't a Klaviyo problem - it's a whole-store problem. Most merchants think if they've got an email flow running and a discount code ready, they're sorted. But the repeat purchase decision is made in the product experience, the delivery, the unboxing, the speed of a support reply. Email just reminds someone of how that felt. If the experience wasn't great, no subject line is saving you. In 2026, with acquisition costs where they are, the merchants winning on retention are the ones treating every post-purchase touchpoint as a marketing moment - not just the inbox.”
So, if email is the reminder and not the strategy, what does an actual retention strategy look like on the ground?
2. How do you typically approach retention for your clients, especially after the first purchase?
"The first thing we do is look at what actually happens after someone buys - and most of the time, it's not much. A generic confirmation email, maybe a shipping update, and then silence. That's a massive missed window.
We start by mapping the post-purchase journey properly. What does the customer receive, when do they receive it, and what does it make them feel? From there we build out the basics - a proper onboarding sequence, a review ask timed to when the product has actually been used, a replenishment nudge if the product warrants it. All of that sits in Klaviyo, where we can personalise based on what someone bought, how much they spent, whether they've bought before.
But the honest answer is that retention strategy lives or dies on the data. We're looking at things like time-to-second-purchase, category cross-sell opportunities, and where customers are dropping off. Once you can see the patterns, you can start building flows and on-site experiences that feel relevant rather than generic.
The goal is always the same - make the second purchase feel like a natural next step, not an afterthought."
That framework has been working for a while. But the tools inside it are shifting fast.
3. How are you seeing AI change the way brands handle retention and re-engagement right now? Any tools or approaches you're particularly excited about?
"The most interesting shift we're seeing is AI moving from a content generation tool to a decision-making layer. A year or two ago, everyone was using it to write subject lines faster. Now the smarter brands are using it to decide who gets what message, when, and through which channel - and that's a much bigger deal.
Within Klaviyo specifically, the predictive analytics have got genuinely useful. Predicted next order date, churn risk scores, lifetime value projections - these aren't gimmicks anymore. When you build segments and flows around that kind of data, you stop blasting your whole list and start having conversations that feel almost eerily well-timed.
Outside of that, we're watching the personalisation layer on-site get more interesting. Recommendations that adapt based on behaviour in real time, landing pages that shift based on where someone came from - it's closing the gap between what email promised and what the website actually delivered when someone clicked through.
What I'd caution against though is reaching for AI tools because they're new. The fundamentals still apply - you need clean data, a clear understanding of your customer, and a post-purchase experience worth coming back to. AI amplifies what's already there. If the foundation is shaky, it just amplifies the problems faster."
The warning at the end of that answer is doing real work. So is the evidence.
4. What kind of results have you helped clients achieve in terms of retention or repeat purchases? Any metrics or notable wins?
“One that stands out is Two Stacks Whiskey - a premium Irish whiskey brand we worked with on a full Shopify build and international expansion through Shopify Markets. They hit a 43% returning customer rate, a 13% increase in average order value, and 734% order growth. For a drinks brand where repeat purchase behaviour can be tricky to build - people are loyal to a product but not always to a website - those numbers meant a lot.
On the B2B side, Bellamianta is one we're proud of. A 9.19% conversion rate and an 81% returning customer rate on their wholesale store. That kind of loyalty in a B2B context doesn't happen by accident - it comes from making the reorder experience genuinely easy and the relationship feel looked after.
BLK BOX Fitness is another good one - a 17% revenue increase year on year, with a 49% jump in traffic and a 53% improvement in add-to-cart rate. Not purely a retention story, but when you improve the on-site experience that meaningfully, you're building the kind of brand people come back to.
The common thread across all of them is that the numbers moved when the whole experience improved - not just the emails. Retention is always the outcome of something bigger.”
What this conversation tells us
Three brands, nothing in common on paper. Two Stacks Whiskey is a premium Irish DTC drinks brand.
Bellamianta sells wholesale beauty. BLK BOX Fitness is gym equipment.
If you were briefing a retention strategy, you wouldn't start from the same place for any of them. But the pattern holds across all three. The experience improved, so the numbers followed.
The 43% returning customer rate at Two Stacks and the 81% at Bellamianta are worth writing down. Most Shopify stores don't get close, and in most cases, the gap isn't in the email strategy. It's in the forty-eight hours after the order ships.
On AI, Daniel's answer is more grounded than most of what's being written about it right now. Klaviyo's predictive analytics aren't new, but they're at a point where building segments around churn risk scores and predicted next order dates makes a genuine difference to who gets contacted and when. That's a more useful problem to solve than faster subject lines.
The warning stands, though. AI running on thin data and post-purchase silence doesn't fix retention. It just puts a fancier engine in a car with no wheels.
What to take from this
- Post-purchase silence isn't neutral. Every brand has a post-purchase experience, whether they designed one or not.
- The time to second purchase is the number that tells you where people are falling away. If you don't have it, the rest of the data is guesswork.
- Klaviyo's predictive data (churn risk, next order date, LTV projections) is worth building segments around now. The logic changes when you're working with intent signals instead of just history.
- AI is a timing and targeting tool, not a replacement for the experience itself. It surfaces what's already there, good or bad.
- The second purchase is decided before you send anything. Get the first forty-eight hours right.
Are you a Shopify agency working to improve retention for your clients?
The Flits Agency Interview Series is open. If you're working on retention and have something worth saying, we’re all ears.
