How many of your customers buy again, and how soon?
When sales slow down, or a big sale is coming (Black Friday, Christmas, end of season), the first move is usually more ads. More budget, new audiences, new creatives.
But the easiest sale you can make is to someone who already bought from you. They know your brand. They trust the product. You already paid to get them once.
So before you spend more on ads, it's worth checking: are your customers coming back, and how often?
Why past customers don't come back
In my experience, it's rarely because they didn't like you. It's usually one of these:
- Nobody asked. They bought in March. The next email they got was the Black Friday sale in November.
- Every email is a discount. 10% off, then 15%, then 20%. So they wait for the next one and stop buying at full price.
- The first order let them down. The parcel came a week late, and nobody answered their email. They didn't complain. They just didn't come back.
- The reminder came at the wrong time. Say a bag of coffee lasts about a month. A reminder in week one is too early. By week ten, they've already bought from someone else.
- They forgot you. Your last email was four months ago. Another brand emailed them yesterday.
Most of these never show up in your sales report. Sales still come in, so nobody looks.
5 simple checks
You don't need a new tool for these. Your store and email platform already have the answers.
1. How many of your customers come back?
Look at the last 3 months. Of the customers who ordered, how many had bought from you before? In Shopify, the "New vs returning customers" report shows this.
2. When did your past buyers last hear from you?
Since their last order, have you sent them anything that wasn't a sale? A thank-you, a how-to-use tip, a "time to restock" reminder? If the answer is no, or it's been more than a month, they've gone cold.
3. How long does it take for a customer to buy a second time?
Look at the customers who did come back. How many days between their first and second order? Anyone who has gone past that point without buying again is drifting away.
4. What did your last customer actually get from you after buying?
Pick a recent order and look at every email that customer received. Helpful looks like: how to use it, care tips, what to expect when it arrives, a "running low?" reminder. Not helpful: three sale emails in a row.
5. If they open your emails but don't buy, where does it stop?
Opened but didn't click? The email isn't giving them a reason. Clicked but didn't buy? The offer or the product page is the problem. Each one has a different fix.
What I've seen
I've built and managed email flows and campaigns, like Black Friday, End of Financial Year, and more.
In one account I reviewed, almost all the money from automated emails came from people who hadn't bought yet. The emails to existing customers were opened just as often, but almost nobody bought again. The repeat side usually gets the least attention. It's one of the first gaps I look for now.
The numbers point the same way. In Klaviyo's report on Black Friday to Cyber Monday 2025, sales from repeat customers grew 13.5%, faster than overall sales at 11%. And the brands with the smallest discounts grew the most (14%). That's Klaviyo's own data from its customers' stores, so treat it as a signal, not a rule. (Source)
What to fix first
After finding that gap, I started building emails for existing customers. A simple set to start with:
| Why | When to send | |
|---|---|---|
| Thank you, plus what happens next | They feel looked after from the start | Same day as the order |
| Shipping and what to expect | No "where's my order?" worry | While it's on the way |
| How to get the most out of it | They use it and like it | A few days after it arrives |
| Check-in or restock reminder | Brings them back at the right time | Just before it usually runs out |
| Win-back, with a reason to return beyond a discount | Catches them before they forget you | Once they pass your usual time to a second order |
| Annual check-in | Wakes up the ones who went quiet | 6–12 months after their last order |
These are a good starting point, not fixed rules. Adjust the timing to how long your product lasts.
In Klaviyo or Mailchimp, these are automated emails that start when someone places an order. "After it arrives" only works if your delivery tracking is connected to your email tool. In Shopify, the "Returning customers" and "One-time customers" reports show who to focus on.
Before Black Friday: let your repeat buyers in first
Give them early access, or a better offer than strangers get, before your main sale and ads start. You reward the people most likely to buy, you sell before ad costs and competitors peak, and you don't need a blanket discount for everyone.
What this actually takes
To do this properly, you pull your sales by new and returning customers, your email history by customer, your order dates, and your returns and support tickets. Then you match them up, one customer journey at a time, to see where people drop off and why.
You can do it yourself. It's just slow, careful work. And it usually lands right when you should be planning the next campaign.
This is the kind of line-by-line work we do at KATOS. See how we handle it →
Common questions
What is a returning customer?
Someone who has bought from your store more than once. In Shopify, the "New vs returning customers" report shows how many you have.
Why do customers buy once and never come back?
Usually because nobody followed up, every email was a discount, the first order had a problem, the reminder came at the wrong time, or they simply forgot the brand.
What should I check before spending more on ads?
How many of your customers come back, when your past buyers last heard from you, and how long it takes customers to buy a second time.
How do I check if my customers are coming back?
In Shopify, the "New vs returning customers" and "Returning customers" reports show it. Your email tool (like Klaviyo or Mailchimp) shows who opened and bought from your emails.