Klaviyo List Hygiene: A 15-Minute Cleanup Checklist
List hygiene is the part of a Klaviyo account most people skip, mostly because it feels tedious and doesn't produce an obvious “win” the way a new flow does. But it's quietly connected to almost every deliverability problem we've covered in previous posts. Here's a checklist you can actually get through in about 15 minutes.
1. Check for an unengaged-suppression segment (2 minutes)
Search your segments for anything named “unengaged,” “cold,” or “suppressed.” If nothing exists, this is your highest-priority fix — it means every regular campaign is still going out to subscribers who haven't opened anything in months. That directly drives up your spam complaint rate and drags down engagement metrics that inbox providers use to judge your sender reputation.
If it doesn't exist: create one, at minimum excluding anyone with zero opens in the last 90-180 days, and reference it as an exclusion filter on your regular campaigns.
2. Find and clean up dead segments (3 minutes)
Go through your segments list and look for anything showing 0 profiles. These don't actively hurt anything, but they're a sign the account hasn't been maintained consistently — and they make it harder to trust that other segments are accurate. Delete them, or archive if your workflow needs a record.
3. Check for near-duplicate segments (3 minutes)
Look for segment names that are almost identical — “VIP Customers” and “VIP Customer,” or “Newsletter Subscribers” and “Newsletter Signups.” These usually mean someone recreated a segment instead of finding the existing one, and now you likely have inconsistent logic between them. Pick one, update anywhere the other was referenced, and delete the duplicate.
4. Confirm your sunset flow is actually suppressing sends (5 minutes)
Having a win-back flow isn't the same as having it correctly suppress cold subscribers afterward. Open the flow and check: after someone goes through it without re-engaging, are they actually added to your unengaged-suppression segment (from step 1) and excluded from regular sends? A win-back flow that doesn't feed back into suppression is only doing half its job.
5. Spot-check your list growth source (2 minutes)
If you've imported any list in the last few months — from a previous ESP, a co-marketing partner, an in-person event — check whether those contacts are behaving differently (lower opens, higher bounces) than your organically grown list. Imported lists are the most common cause of a sudden deliverability drop, and it's worth knowing if that's a factor before it becomes a bigger problem.
None of these steps are individually complicated, but skipping all five is exactly how list hygiene issues compound quietly over months until they show up as a real deliverability problem. If you'd rather see all of this checked automatically instead of going through it by hand, Fluxchek scores your account's list hygiene as part of a full audit in about 60 seconds.