Learn how to clean up your Klaviyo account this summer for a more successful BFCM.
Nothing says summer like long weekends, OOO replies, and a Klaviyo account full of disengaged profiles.
Every summer I have a version of the same conversation with clients. Someone notices their open rates are softer than usual, clicks have flattened, and they're not sure if it's seasonal or something they should actually worry about. Most of the time, it's both.
Summer is when engagement quietly softens. The list you've built over the past year starts carrying more weight than it should, and the fixes that would have taken a weekend in July turn into a scramble in October. The good news: a slower summer period is the right time to get ahead of it.
Why does list hygiene matter before Black Friday Cyber Monday?
Inbox providers use engagement signals to decide where your email lands. When a meaningful chunk of your list stops engaging, those providers start treating you like a sender they're less sure about. That's not just softer open rates. It's slower inboxing, more Promotions tab, and more spam folder. An unengaged list not only underperforms; over time, it actively pulls your sender reputation down with it.
Sender reputation is built on a small set of signals: hard and soft bounces, spam complaints, unsubscribes, and whether you're hitting spam traps. Every one of those gets worse the longer you carry disengaged contacts on your list. The list you send to in November is only as strong as the hygiene work you do before it.
That's the argument. Here's the work.
The rest of this is a checklist. Five steps, in order, that'll get your account in shape before Q4.
✔ Check deliverability health and get a baseline on KPIs
✔ Find and segment your unengaged contacts
✔ Build and run a sunset flow before suppressing anyone
✔ Run a 30-minute flows audit before Q4
✔ Use Audience Optimization at send time (Marketing Analytics tool)
Read through the whole thing first, then start at the top.
How do you check deliverability health in Klaviyo?
Before you change anything, get a baseline. You can't fix what you haven't measured, and you don't want to suppress 20% of your file based on a vibe.
In Klaviyo, go to Analytics > Deliverability. The email deliverability hub shows your open, click, bounce, spam, and unsubscribe rates across recent sends. For a longer view across the account, use the Business review dashboard.
What I actually look at:
Bounce rate over ~1% on a regular basis. One bad send isn't a story. A pattern is.
Spam complaint rate over 0.1%. Gmail's postmaster threshold to start hurting you sits around 0.3%, so 0.1% is your early warning.
Unsubscribe rate trending up campaign over campaign. That's usually the first sign your "engaged" segment isn't as engaged as the name suggests.
Quick note on bounces: hard bounces are permanent. Bad address, no longer exists. Klaviyo automatically suppresses these on the first hard bounce, so you don't need to manage those manually. Soft bounces are temporary (inbox full, server down, message too large), and one isn't a problem. A repeat soft-bouncer over multiple sends is worth a closer look.
For more on interpreting these numbers, getting started with email deliverability monitoring and performance metrics is a good starting point.
How to find and segment unengaged contacts in Klaviyo
Step 1: Build multiple unengaged segments to have a few numbers to reference.
Step 2: Spot-check profiles in the segment to make sure it's pulling in truly unengaged people and not active subscribers.
Step 3: Run a sunset flow and push these people through it.
Step 4: Suppress the non-responders for a length of time that makes sense for your brand's lifecycle.
Build the segments.
Go to Audience > Lists & segments > Create new > Segment.
Build out the definition of a 90-day unengaged contact like this:
| Person can receive email marketing AND Received Email at least 5 times over all time AND Opened Email zero times in the last 90 days AND Clicked Email zero times in the last 90 days |
Building 90/180/365 versions side by side lets you see what percentage of your file falls into each bucket before you cut anything. Other segments to build for list cleaning based on how aggressive you want to be:
| Unengaged 180 | Person can receive email marketing AND Created at least 180 days ago AND Person has Received Email at least once in the last 180 days AND Person has Opened Email zero times in the last 180 days AND Person has Clicked Email zero times in the last 180 days AND Person has Active on Site zero times in the last 180 days AND Person has Placed Order zero times in the last 180 days |
| Unengaged 365 (Email + SMS) | Person can receive email marketing AND Person has Received Email is at least 10 in the last 365 days AND Person has Clicked Email zero times over all time AND Person has Placed Order zero times in the last 550 days AND Person has Clicked SMS zero times over all time |
| Unengaged: no purchases in 2 years (for older accounts that need a deep clean) | Person can receive email marketing AND Person has Received Email is at least 75 over all time AND Person has Clicked Email zero times over all time AND Person has Opened Email zero times over all time Where Apple Privacy Open is false AND Person has Placed Order zero times in the last 730 days |
Two caveats worth knowing:
The window you pick — 30, 90, 180, 365, etc. — depends on the brand. Three things drive it: your purchase cycle, how aggressive you want to be about cutting list weight, and what your own data tells you about when a lapsed contact is actually unreachable. A coffee subscription brand and a luxury furniture brand should not be using the same number. If you can, pull your re-engagement rates by lapsed duration and find the point where they fall off. That's your real threshold. If you don't have that analysis yet, 90 days is a defensible starting point, not a universal answer.
If you migrated from another ESP recently, Klaviyo only sees engagement data from after the migration. If your 90-day window overlaps the migration date, add conditions that pull in historical open and click data from the imported source. You'll flag people who were actually engaging with you, just on a different platform.
Use the never engaged shortcut where it fits.
Analytics > Deliverability > Action center has a Create a never engaged segment option. Klaviyo builds it automatically with stricter criteria: received 5+ emails in 180 days, never opened, never clicked, never viewed a product, never placed an order. That's your hardest-cut group, and it's the right segment to suppress in bulk after a sunset attempt.
There's also a community post on list cleaning methodology written by another Champion that gets into segment set-up and timing in more detail than the help docs, if you want a practitioner-level read. And how to clean your email list to maintain good deliverability covers suppression best practices once your segment is built.
Should you run a sunset flow before suppressing contacts?
Before you remove anyone for good, give them one last chance to come back. That's what a sunset flow is for.
A standard set-up:
Trigger: a metric like Placed Order with a long lookback, or a segment trigger when someone newly enters your unengaged segment (both are valid approaches).
Profile filter: hasn't opened or clicked in 90+ days.
Sequence: usually three emails over about three weeks.
Email 1: soft, no discount. A reminder of what they bought or browsed, or a top-product nudge.
Email 2: an offer, if you have margin for it.
Email 3: explicit last chance. "We'll stop emailing you unless you tell us not to." This one actually performs.
One option worth adding to the final email: an opt-down link alongside the unsubscribe. Some people aren't unengaged because they've moved on. They're unengaged because you email three times a week and they only want once a month. Letting them dial back instead of fully unsubscribing keeps the relationship alive and protects you from the spam complaint that would otherwise come on send four.
What you do with non-responders after the flow runs is the real cleanup. Go to Lists & segments > [your Never engaged segment] > three-dot menu > Suppress current members to bulk-suppress.
The honest caveat: a sunset flow takes time. A three-week sequence, plus the engagement window after to see who came back, means you want this running now if you want it wrapped before Q4 ramp. Klaviyo's deliverability team explicitly recommends starting at least three months before BFCM.
If you want more on the mechanics, the sunset flow set-up guide and the community thread on winback flow strategies both go deeper. The active profile management overview is worth reading if you haven't.
What should you audit in your Klaviyo flows before Q4?
Not a Klaviyo feature, just a habit. Pick a slow afternoon and click through every live flow.
What I'm looking for:
Outdated product references. The hero product from 18 months ago that's been discontinued. The "as seen in" feature from a launch that's two seasons old.
Broken links. Especially links to landing pages or collections that don't exist anymore.
Stale timing logic. A "checking in 6 months later" email that made sense when the flow was built, but doesn't fit the journey now.
Flows untouched since last BFCM. Seasonal copy that was supposed to be temporary.
Triggers off metrics you've renamed or stopped using. This one's sneaky. The flow looks live but isn't actually firing.
While you're auditing, look at what metric your flows are reporting on. If you're still measuring everything by open rate, opens have been an unreliable signal for years. Apple Mail Privacy Protection inflates them, and the trend isn't reversing. Clicks, on-site behavior, and recent orders are all closer to the truth.
This is the kind of work that feels optional until October, then suddenly urgent. Klaviyo's BFCM checklist guide explicitly calls out flow optimization as a task, and their email deliverability best practices guide is good supporting context on why flow hygiene affects sender reputation, not just performance.
What is Audience Optimization in Klaviyo and who has access to it?
Worth mentioning because a lot of operators don't know it exists: Audience Optimization is a pre-send toggle in the Audience step of email campaigns (both single-channel and omnichannel). It uses a predictive model to remove recipients who are most likely to unsubscribe from that specific send, before the send goes out.
To be clear about what it is and isn't: it's not a list-cleaning tool, and it's not a replacement for the hygiene work above. It runs at send time, on that send only. The list-level work, like sunset flows, segmentation, and suppression, still has to happen. Audience Optimization sits on top.
Plan caveat, plainly: it's available to customers on Marketing Analytics or the Advanced Klaviyo Data Platform. Not every account has it. If you do, the place to start is turning it on for campaigns going to your broader engaged audience and watching the unsubscribe rate over a few sends. Klaviyo's Audience Optimization help doc covers configuration.
Wrapping up
None of this is complicated work. It's just work that's easy to push to later, and later, in this business, is usually November. The whole point of doing it in summer is that you have the bandwidth to do it carefully, let the sunset flow actually run, and walk into Q4 with a list you trust.
A cleaner account in August is a stronger sender in November. That's most of the argument.
Reply below!
What does your summer account audit actually look like? Is there a step you always do first, or something you've added to the routine after a painful Q4?