Hey, Anthony from The Retention Report here. A long-time client of ours came to us a few months back with a simple question.

"Could we build a flow just for our hero product?"

It's the SKU that drives a serious chunk of their overall revenue.

The one that when it performs well, the whole business feels it.

And up until that point it was sitting inside the same evergreen post-purchase flow as everything else in their catalog wiht the same timing, emails, and advice as a product that sells a tenth of the volume.

The answer was obviously yes.

But it made us think harder about why more brands aren't doing this already, and why we didn’t do it earlier…

If you want to understand how we did it, the result, and how you can do the same for your brand, keep reading…

Before we go further, I want to say something that might be unpopular.

Most hyper-segmented, hyper-personalized email flows are not worth the time it takes to build them.

Splitting your flow by gender, by age range, by how someone found you, by what color variant they bought, in most cases the juice is not worth the squeeze and the incremental lift doesn't justify the complexity.

But there's a version of personalization that's almost always worth it.

When you have a product that is doing serious volume for your business, a true hero SKU that a large portion of your revenue runs through, building a dedicated flow around that specific product's buyer is one of the highest-leverage things you can do in Klaviyo.

The personalization isn't for the sake of it.

It's because that product matters enough to deserve the attention, and that buyer is valuable enough to treat differently.

Thats the line worth drawing. Not personalization everywhere. Personalization where it actually moves the needle.

Here's what most brands do.

They build one post-purchase flow, feel good about having it, and never go back.

Which makes sense because building flows takes time and there are always campaigns to send and fires to put out.

But that one-size-fits-all approach treats your customer list like a single audience when in reality every product you sell attracts a slightly different person with slightly different needs.

Your sleep formula buyer wants to know when they'll actually feel it working.

Your greens powder buyer wants to know the best time to take it and what to mix it with.

Sending them the same email at day seven isn't just lazy. It's a missed opportunity that compounds with every single send after it.

Forget the generic 30, 60, 90-day timing.

Build the replenishment trigger around actual product usage and the typical re-purchase window for the product (excluding subscriptions).

For a sleep product that's "when will I feel it, is it normal to feel groggy, should I take it every night or just when I need it."

For a pre-workout, that's "how long before training, can I stack it, why does it make my face tingle?"

Here’s what ours looks like:
- Email 1: Thank you + product story + set expectations | Immediately
- Email 2: How it works + credibility (in this case, referencing their sleep study) | Day 2
- Email 3: Sleep protocol + lifestyle tips specific to the product | Day 3
- Email 4: Product survey with an incentive | Day 15
- Email 5: Highlight subscription savings | Day 23
- Email 6: Follow-up | Day 30


These aren't complicated emails to write. They're just specific.

If someone bought your magnesium, the next logical product for them is probably not your best-selling protein.

It might be your zinc, your ashwagandha, your sleep formula.

The connection has to feel like a natural recommendation from someone who actually knows what they bought.`

So what happened?
- A double-digit (and in some cases triple-digit) increase in nearly every single first-order + retention metric across the board, comparing when we first launched the flow versus the previous period
- Average repurchase window went from 50 days → 41 days → Now last 90 days, it’s been around 30 days
- Extremely strong engagement metrics

Nothing changed about the product. Everything changed about how they talked to the person who bought it.

And because that SKU represents a significant portion of their overall revenue, an even 12% lift in repurchase revenue on that one product moved the needle for the entire business.

That's the point.

You don't need to personalize everything.

You need to personalize the thing that matters most.

Pull your top-performing SKU in Klaviyo.

Look at who's buying it.

Look at what they buy next if they do come back.

Look at how long it typically takes them to reorder.

That data is already sitting there and it'll tell you everything you need to know about what this flow should say and when it should send.

Then write three emails.

One that goes out two days after purchase that answers the single most common question a new buyer of that product has.

One that goes out at the natural midpoint of the product's usage cycle that reinforces why they made a good decision.

And one that goes out a week before they're likely to run out that makes reordering as easy as possible.

Thats your starting point. Build the rest of the flow around those three.

If you want a second pair of eyes on how your current post-purchase setup is treating your best SKU's buyer, reply with the word FLOW and I'll show you exactly what I'd look at first.

— Anthony

P.S. This works in any category with a usage cycle or a learning curve. Skincare, supplements, pet nutrition, coffee, cleaning products. If someone has to figure out how to use it or will eventually run out of it, they need a SKU-specific flow.