Most customers buy once and disappear. A reminder system fixes that.
You already know the stat. It costs five to seven times more to acquire a new customer than to keep an existing one. But knowing it and doing something about it are two different things.
The businesses that grow steadily are not the ones with the biggest ad budget. They are the ones that figure out how to get customers to come back without paying for another click.
A repeat purchase reminder system does exactly that. It watches what people buy, calculates when they will need it again, and sends the right nudge at the right time. No manual follow-up. No guesswork. Just automated revenue from people who already trust you.
Here is how to set one up.
Step 1: Map out your repeat purchase cycles
Not every product has a natural reorder cycle. A candle might last six weeks. A pair of socks does not. Start by listing every product in your store and estimating how long a typical customer takes to use it up or replace it.
Be specific. “About a month” is not useful. “32 to 38 days for regular buyers” is. Look at your order data. Filter for customers with two or more purchases of the same product. Measure the average gap between orders.
If you sell on Shopify, go to Analytics then Reports then Sales by Product. Export the data and sort by repeat purchases. You will see patterns fast.
Write down each product, its estimated reorder window, and the trigger point (how many days after purchase to send the reminder). This becomes the backbone of your system.
Step 2: Set up automated email triggers
Most email platforms support time-based automations. Klaviyo, Mailchimp, Omnisend, and Drip all handle this out of the box.
Create a flow for each product cycle:
- Trigger: Customer completes an order containing Product X
- Wait: The number of days from your reorder window minus 5 (send slightly before they run out)
- Email 1: “Running low?” with a one-click reorder link
- Wait 3 days: If no reorder, send Email 2: “Still need more?” with a small incentive
- Wait 5 days: If no reorder, send Email 3: “Last chance” with free shipping or 10% off
Keep the copy short. You are not writing a newsletter. You are sending a timely reminder. Two to three sentences max. A clear subject line. One call-to-action button.
Step 3: Add SMS for high-intent products
Email open rates for transactional reminders hover around 40 to 50 percent. SMS hits 90 percent. If you sell products with short reorder cycles (under 30 days) or high price points, SMS is worth the extra cost.
Use the same trigger logic but send an SMS instead of, or in addition to, the first email. Keep it even shorter: “Hey [Name], your [Product] is probably running low. Reorder here: [link]”
Most platforms let you combine email and SMS in a single flow. Set email as the primary channel and SMS as the fallback for customers who have not opened the email within 24 hours.
Step 2: Personalise the reminder content
A generic “we miss you” email gets ignored. A reminder that references the exact product they bought, in the size or variant they chose, with a reorder link that pre-fills their cart, converts.
Use dynamic blocks in your email platform to pull in:
- The product name and image
- The exact variant (size, colour, quantity)
- A pre-filled reorder URL
- Their first name
The less work they have to do, the more likely they are to click.
Step 5: Track and optimise
After 30 days, check the numbers:
- How many reminders were sent?
- What percentage resulted in a reorder?
- Which email in the sequence converted best?
- What was the average time between reminder and reorder?
Use this data to tighten your reorder windows. If most people reorder at day 28 but you are sending reminders at day 25, move it closer. If Email 2 outperforms Email 1, your subject line on Email 1 needs work.
The goal is not perfection on day one. It is a system that gets better every month.
You already have the data. Use it.
Every order in your store tells you what someone bought, when they bought it, and how much they spent. That is everything you need to build a reminder system. The only question is whether you act on it.
Start with your top five most-reordered products. Build the flows. Run them for two weeks. Watch the numbers. Then expand.
The customers who come back are the ones who drive 80 percent of your revenue. A reminder system makes sure they do.
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