What is a Replenish Email?
A replenish email, also known as a re-order email, is an email that reminds customers to return to your store to re-purchase items they have previously purchased. It can also contain an upsell call to action (CTA) that suggests new, related items to try.
Replenish email benefits include:
- They are ideal for products designed to be re-ordered on a regular basis. These include consumables like food, treats, supplements, shampoos, medications, and sometimes toys.
- They incorporate seasonal discounts like holiday offers, Mother's Day and Father's Day gift suggestions, and reminders for special occasions like birthdays.
- They build trust and rapport with your customer who appreciates the reminder before they run out of the products they use regularly.
- They offer merchants the opportunity to personally connect with customers who already purchase from your store.
- Re-engaging with a repeat customer is much less expensive than acquiring new customers. A solid replenish email system can free up your advertising dollars to acquire new customers.
In a Google search you can find plenty of replenish email blogs and visual email examples as well as instructions for how to analyze customer data with Excel, create look-alike audiences, customer segments, and workflow automations to optimize email cadence for delivery.
Several software tools say they do this work for you, yet they are expensive, complicated to set up and use, and still require a dedicated person to segment audiences and create, monitor & adjust automation flow diagrams.
This article is not about the old-fashioned way of doing replenish emails. Here we discuss how Artificial Intelligence is altering the landscape of re-engaging with customers, making it easier and more effective.

First-Party Data & AI Fuel Potent Replenish Emails
The next generation of replenish emails uses first-party customer information in concert with Artificial Intelligence (AI) to automatically optimize and personalize email content, offers, product selection, and delivery cadence per individual customer.
With the sunsetting of third-party data collection due to increased global privacy regulations, the collection of first-party data has become critical. Doing it correctly is a foundational piece for replenish email setup and execution. The caveat is that you need to convince customers to share their information with you.
Major e-commerce platform like Shopify already collect specific pieces of personally identifiable information (PII) from customers when they visit or purchase from your store. However, true first party information that feeds AI driven replenish emails must go one step further. This next level of information is collected and stored in the Shopify app that you use to extend Shopify's functionality.
For example, with PetPro AI, we created a pet profile entry form to collect information about a customer's pet(s) and store that in our encrypted database. This first party information appears alongside Shopify's customer information in the store environment and is available to both the customer and the merchant. Merchants can now see this collected first party data in the regular Shopify customer screens and use it to hyper-personalize their interactions with customers. It also fuels the hyper-personalized replenish emails that get sent to customers.
Trust is a key factor in customers sharing information with a merchant because, according to Google, 80% of consumers are concerned about the state of online privacy. The key is to be transparent about how you handle and store information customers share with you. Let them know what you will do with their information, and, more importantly, what you WON'T do with their information. Give customers the ability to change their mind about sharing information with you and easily delete it.

One tremendous benefit of doing AI driven replenish emails is that it simplifies the process of setting up personalized outreach to customers. You no longer need to calculate customer purchase frequency in Excel, create customer segments that approximate activity level and preferences, or create workflow diagrams with "if/then" arguments for actions customers take or avoid.
A next generation AI driven replenish email system will automatically generate and send replenish emails to your customers, enabling you to focus on other important tasks of running a successful e-commerce operation. These emails will:
- Automatically consider the most optimal delivery timing and frequency.
- Personalize subject lines and email body content with hyper-relevant information.
- Automatically create discounts & incentives for products they buy regularly.
- Offer upsells based on customers with the same purchase history & first party information.
BCG reports that "data driven marketing can double revenue and increase cost savings by 1.6 times".
5 Important Email Stats to Know
- Replenish emails have a 53.6% open rate, the highest of any type of email, according to Listrak. The nudge to re-order something a customer uses regularly is appreciated and rewarded by conversion.
- Of the emails opened, 81% of emails are opened and read on mobile devices. Mobile phones, which we carry with us all day long, have become the de facto standard for regular communications and transactional activity.
- 69% of email recipients will report spam based on a bad subject line. An AI driven replenish email system will automatically optimize and personalize the subject line, dramatically decreasing spam reporting. Personalized email subject lines increase email open rates by at least 50%.
- AI driven personalization is being used by 9 in 10 (92%) businesses to drive growth.
- 90% of consumers are willing to share personal data with a merchant when offered the right value exchange. The highest value drivers include discounts and free samples for products they want. See chart below from BCG outlining the top reasons people share information with merchants.

3 Ways AI Driven Replenish Emails Deliver Results
Replenish emails are sent to customers to coincide with the timing of their last purchase. The theory is that they are running low and will need to repurchase, so nudge them in that direction.
Replenish emails that employ AI technology are simpler to setup and manage while optimizing engagement and conversion. This is because data about the customer is integrated into one platform instead of being siloed.
1) Optimizes Delivery Timing Automatically
When should you send replenish emails to your customers? Too often or at the wrong interval can result in a high level of attrition through unsubscribes. Too little can result in customers forgetting to buy at regular intervals that keep their cabinets stocked. How can you tell the right timing to send replenish emails?
There are three ways to determine the proper cadence: analyze buying patterns with Excel, segment customers, or automate using artificial intelligence. We examine all three below.
a) Old Way: Analyze Customer Buying Patterns with Excel
The old way of figuring out when to send replenish emails is tedious and time consuming and requires that you analyze average customer purchase frequencies by adding up total purchases made over a set period of time and dividing that by the number of distinct customers buying during that period of time. This requires an intermediate level of Excel knowledge and regular spreadsheet maintenance to calculate the average purchase frequency. Then you have to keep the spreadsheet current, repeating the calculation process regularly. If you have a varied catalog, you will be doing this for each customer and each category of product you carry.
b) Old Way: Segment Customers into look-alike audiences
A newer way of configuring replenish email timing is to let the software assist in the process. These software programs schedule the replenish email a few days in advance of the actual date of last purchase or the normal cadence of purchase. Most of these software tools use customer segments that you create based on things like behavior, purchase history, geography, demographics, etc. These software solutions improve the cadence of replenish emails, but they still require the merchant to create customer segments and rely on bulk customer information instead of individualized customer activity.
c) New Way: Automatically Generate Emails with AI
The most efficient way to schedule replenish email is to let the software do it for you. The newest software solutions already know your customers' information, shopping history and buying patterns, down to the minute. They also know first party information about your customers that you have asked them to share with your store. Replenish emails that utilize AI can be highly individualized for each and every customer and automatically sent at just the right moment.
PetPro AI offers hyper-personalized, automatically generated replenish emails because they are enhanced by first party information that customers share with merchants about their pets. The software handles all of the details automatically.
2) Hyper-Personalizes Outreach Content
What are the components of a hyper-personalized replenish email? In the current state of AI and digital marketing, this is still a wild west frontier with so many untapped possibilities for personalizing contact with customers.
AI driven replenish emails hyper-personalize outreach in several key ways, outlined below:
- Including a customer's name in the subject line or body of an email can increase open rates by 50%.
- Information you know about customers' routines, habits, sizes and preferences allows you to personalize the email with pieces of that information and build a connection with the customer.
- AI systems can quickly present a variety of styles of subject lines and content options that better match your store's voice or tone.
- Creating a highly relevant message for a specific CTA , like an abandoned cart or "sale ending soon" nudge.
- Sending a personalized email in advance of a customer's or family member's birthday with a discount coupon reminds them to make a purchase and demonstrates that you know and care about them.
- Create location and time specific offers like a "Midwest Stock-Up Sale" or "Beat the Holiday Rush" event. These can be individualized to speak directly to customers and offer specific products for their families.

3) Creates Helpful and Meaningful Customer Exchange
Replenish emails, by their very nature, are designed to put the same previously purchased product back in front of your customer. The key to making the replenish email helpful and meaningful is to show the customer that you "see" them and are cultivating a trusting relationship with them. This is where AI and first party data begin to shine.
When you have first party information about a customer and the products they have purchased before, you have the building blocks to make relevant suggestions for other products they could find useful.
At PetPro AI, our focus is pets. We enable merchants to gather information from customers about their pets that fuels their communications back to them. Our task is to enable merchants to suggest deeply relevant information to customers for the benefit of their furry families.
Laser focus your targeting on nudging customers to re-purchase the same product. Encourage them to try a truly relevant new product. Then sweeten the deal with a promotional discount. Simplify the CTA and make the reward potent. This "relationship building" with customers builds trust and loyalty and protects the customer's valuable time.
Recommended Reading
Subject Line Examples We Love by Drip.com
15+ Email Subject Line Statistics 2023 by Zippia
Consumers Want Privacy: Marketers can Deliver by BCG
Driving Growth in a Changing Privacy Environment by Think with Google