The Complete Guide to List Hygiene

Last updated Oct. 02, 2020

This is a COMPLETE guide to list hygiene.

In this post you’ll learn:

What list hygiene is
Why it’s important
How to clean up your email list
Lots more

Let’s dive right in.

What Is List Hygiene?

List hygiene is the continuous process of removing inactive subscribers from an email list in an effort to improve deliverability and open rates.

How List Hygiene Changed My Entire Business

Hi, I’m Brian Dean.

A few years ago, my email marketing was going great.

My list was growing quickly. My open rates were fantastic. And my newsletters were staying out of the spam folder.

Then, out of nowhere, my open rates took a nosedive.

My open rates went from 45%…to 32.5%… all the way down to less than 10% for certain emails.

At first, I was confused.

I knew that open rates usually go down as your list grows.

But that was supposed to be a gradual thing.

But my open rate problem? It came out of nowhere.

One day my open rates were outstanding. Literally two months later… they were horrible.

That’s when I decided to try cleaning up my email list.

Specifically, I looked up how many subscribers hadn’t opened an email from me in 6 months.

And that ended up being 28,018 subscribers!

Put another way, 35.5% of my subscribers were inactive.

It definitely hurt to do. But I ended up unsubscribing all 28,018 subscribers in one day.

As you can see here, I sent this email to my list of 78,919 people.

Then I cleaned up my list.

And that message went out to 50,901 subscribers.

My open rate went from 19.9% to … 28.3% instantly.

Over the next few weeks, my open rate shot back to where it was before.

Today, I clean up my list every month. And I have ZERO email deliverability issues.

The bottom line? List hygiene is one of the absolute best ways to improve your email open rates and get your emails delivered to the inbox.

How List Hygiene Works

Email service providers like Gmail decide to put your message into the inbox based on dozens of different factors, like:

Sender reputation
Your sending server’s IP address
The content of your message
If you’ve sent emails to “spam traps”
Lots of hard bounces
Number of spam complaints

But one of the most important factors is: engagement.

Gmail, Yahoo and Outlook all want to see lots of people opening, clicking on and forwarding your emails.

This tells those email services: “People are LOVING these emails. We need to make sure they end up in our users’ inboxes”.

But when they see that your emails are getting ignored, they think:

“These emails aren’t making users happy. And they’re legally ignoring emails from that sender. Future emails from this person are probably better off in the spam folder”.

This is exactly why list hygiene is super important.

Over time, a certain chunk of your subscribers will simply STOP opening your emails.

Sometimes they changed their email address. Sometimes they left the company they were at when they subscribed to your list. And other times they just stopped being interested in the type of content you’re sending.

The exact reason doesn’t really matter all that much.

The important point here is that subscribers decay over time.

And if you keep them on your list, your engagement rates are going to drop.

But when you clean up your list on a regular basis, you’re ONLY sending to interested subscribers. Which means your engagement rates will stay super high.

In the end this will result in more opens and clicks. Plus, higher deliverability rates.

To be clear: list hygiene doesn’t work overnight. It can take time for email providers to see that people are engaging with your messages again.

Like I mentioned earlier, my open rate improved significantly the week after I cleaned up my list for the first time.

But that’s totally normal. I had much fewer subscribers. And those subscribers were actually engaged.

Here’s the interesting part:

Only a few weeks later, my total opens (not just my open rate) improved too.

Email Total Opens Improved After Cleaning

(Even though I was sending to 33% fewer people.)

That’s because I was finally reaching my entire list. Including people that WANTED to hear from me. But didn’t see my emails because they were going to spam.

With that, let’s cover exactly how to clean up your email list.

List Hygiene Best Practices

1. Delete Inactive Subscribers

Your first step is to login to your email marketing software. And figure out how many inactive subscribers you have.

You might be wondering:

“How do I know if someone is inactive?”.

There are two ways of defining an “inactive” subscribers:

1. They haven’t opened an email from you in 6+ months.

This approach is best if you send a consistent number of emails each month.

That way, you know that 6 months of no opens=they haven’t opened quite a few emails.

2. They haven’t opened your last 10-15 emails.

This approach makes sense if you only send emails now and again.

For example, maybe you have a newsletter that you send out whenever you have something special to share.

Or maybe you run a SaaS company that only sends emails when you launch a new feature.

Either way, in this case you don’t want to consider a subscriber inactive if they haven’t opened in 6+ months. They may have only received 5 newsletters from you over that timeframe.

So they haven’t had a lot of “chances” to open one of your messages.

In my case, I unsubscribe anyone that hasn’t opened one of my newsletters in 6 months.

I send emails pretty consistently. So in my case, 6 months of no opens means that the subscriber has ignored about 20 emails in a row.

Which DEFINITELY means they’re inactive.

Now:

How you actually find these subscribers depends on the email marketing software that you use.

Personally, I use Aweber.

So in my case, I just find people that haven’t opened in 6 months using their “Manage Subscribers” search feature:

And unsubscribe anyone that shows up here from my list.

Whether you use Convertkit or another tool, this process will be pretty much the same.

Pro Tip: Make sure to spot check the people you’re about to unsubscribe or delete from your list.

The LAST thing you want to do is accidentally delete active subs from your list.

Which is why I recommend manually checking a few of your inactive subscribers. And double check that they really haven’t opened anything from you.

I always do this before I hit the “unsubscribe” button. And it’s saved my butt more than a few times.

2. Clean Your List Every Month

List hygiene isn’t something you do once. Or whenever you remember to do it.

For email list hygiene to work, you need to clean up your list every month.

In my case, I have a reminder on Google Calendar to clean up each of my email lists once per month.

If you don’t make list cleaning a regular habit, inactive subscribers will start to pile up. And you can easily run into deliverability problems.

3. Try a Re-Engagement Campaign

You don’t necessarily have to delete inactive subscribers right away.

You can also try what’s known as a “Re-Engagement Campaign”.

A Re-Engagement Campaign is where you send an email to your inactive subscribers.

An email that basically asks them: “Do you still want to get emails from us?”.

Here’s an example of how this might look:

Hey Brian,

I noticed you haven’t been reading our emails lately. So I’m checking in to see if you still want to receive them.

If not, no worries. I’ll unsubscribe you from our list automatically in a few days.

But if you’d like to stay subscribed, just click on this link.

Click Here To Stay Subscribed

And we’ll continue to send you our newsletters like usual.

The obvious benefit of this approach is that you keep some of your inactive subscribers on your list.

And in some cases, you’ll turn inactive subscribers back into active subscribers.

The downside is that this makes your list hygiene process more complicated.

Instead of just deleting subscribers and being done with it, you’re creating an entire process. A process to double check if inactive subs really want to be unsubscribed.

Plus, your re-engagement emails are going to have HORRIBLE open rates.

(Remember, you’re sending this only to people that haven’t opened anything in 6 months.)

Which can make your email deliverability issues even worse.

That’s why I personally don’t use Re-Engagement Campaigns.

If someone ignores one of my emails for 6 months, there’s no point in trying to “re-engage them”.

They’re dead to me 🙂

But seriously, I prefer to keep it simple.

If someone hasn’t opened literally 20 of my emails in a row, they’re clearly not interested in what I’m sending.

So I just unsubscribe them right away.

That said, a lot of people in the email marketing space prefer Re-Engagement Campaigns. So there’s no “right way” to approach it.

I recommend trying out a Re-Engagement Campaign. See how it works for you.

Then, you can decide to add Re-Engagement Campaigns to your list hygiene process. Or not.

4. Segment Your Subscribers

Segmenting your email subscribers is a great way to AVOID inactive subscribers in the first place.

Like I mentioned earlier, people become inactive for a bunch of different reasons.

But one of the main reasons is that you’re sending them irrelevant stuff.

In fact, one survey by MarketingSherpa found that 21% people unsubscribe because the emails weren’t “relevant”.

And another industry study found that 37% of inactive subscribers stay subscribed to a list because they’re expecting more relevant emails in the future.

Enter: segmentation.

With email segmentation, you split up your list into different buckets. And send targeted content to each segment.

For example, Backlinko is a B2B online education company. We have programs about SEO, blogging, course creation and more.

That said: 75%+ of our subscribers are interesting in SEO.

So when we launch a program that’s not about SEO, we segment the list. That way, we’re only sending emails to people that are interested in that specific program.

For example, we recently launched our course about growing on YouTube.

So we first sent out this email to the entire list: