Writing is an exercise in restraint. Good writing, that is. Cut, trim, prune away cruft, goes the most common writing advice, until your thesis shines through like a diamond cut out of the rough.

“A sentence should contain no unnecessary words, a paragraph no unnecessary sentences,” advise Strunk and White in their Elements of Style. “Kill your darlings,” Stephen King repeated and others are claimed to have said. The original, it turns out, was far wordier: “Whenever you feel an impulse to perpetrate a piece of exceptionally fine writing, obey it — whole-heartedly — and delete it before sending your manuscript to press,” said one Sir Arthur Quiller-Couch (as discovered by John Crowley for Harper’s). “Murder your darlings.”

Vicious though it may sound, pruning words is as crucial as pruning hedges, they say. Cut away, ‘till only the best remains. So it is with the email lists where you publish your writing. Your list likely includes dozens if not hundreds of lurkers who drag down your open and click rates while boosting the only metric that costs you money. So cut them, too. The total number of subscribers is a nice totem, but perhaps yet another darling to murder and kill.

Yet it’s never quite that easy.

Fake subscribers are not worth counting

Our golden rule of email lists at Buttondown is simple: “Make sure the only people getting your newsletter are the ones who actually want to get your newsletter.”

That keeps subscribers happy, keeps deliverability high, and preemptively prevents people marking your email as spam to keep it out of their inbox. Win, win.

So no sending emails to people who unsubscribed, no tricking people into getting your emails or staying on your lists, and no sending emails to bots and fake email addresses.

That’s why Buttondown automatically cleans up email lists. Enable subscriber cleanup on your account, and Buttondown will automatically unsubscribe broken, disposable, and spammy email addresses, as well as anyone who’s complained about your newsletter to their email provider or never confirmed their subscription. That keeps you from sending emails that will never be received or that people didn’t really want in the first place.

But should you go further?

The case for pruning your email lists

The conventional wisdom is that you should remove everyone on your email lists who isn’t reading your emails. “Consider unsubscribing recipients who don’t open or read your messages,” advises the Gmail team.

If you email 100 people, and 50 people open your emails and 25 click a link, then your open and click rates are 50% and 25%, respectively. If you remove the 50 people who aren’t opening your emails, suddenly you’d have 100% open rates and 50% click rates.

Not only would that stat feel good, but those higher engagement stats would likely boost your email reputation store with Gmail, Microsoft, and other email providers, giving your emails a higher chance of showing up in new subscribers’ inboxes instead of their promotions tab or—worse—spam folder.

For some people just don’t want to receive your emails—and it’s not worth emailing those people. Say you followed another best practice of creating a lead magnet—a free template or eBook, available to anyone who signs up to your list. Do those people actually want to keep receiving your newsletter? Likely not, found Rosanna, a designer. 

“So many people had been added to the list purely because they wanted the free template download,” she discovered, and “many weren’t interested in what I had to say or sell.” So she deleted a 10,000-strong list, and lost little in the process while gaining savings on what was otherwise a reasonable-sized monthly email bill.

Worse are decades-old lists of unknown provenance. Perhaps the list was built cleanly, one new subscriber at a time, but subscribers slowly forgot about the list as it went dormant. Other times, corporate mergers and sales lists commingling and lack of double opt-in tracking means the Frankenstein lists don’t pass GDPR and other privacy regulations’ rules. 

“A client of ours was sending e-mail to a list they had been building since the late '90s,” wrote Rick Whittington, and “there were a relatively high number of spam abuse complaints when we sent the mailings.” The only thing worse than lack of interest is negative interest.

That’s when it’s best to cut the cruft and clean your email list. In general, the numbers seem to play out. SharpSpring in 2020 found that, after cleaning 5,000 email lists and cumulatively sending half as many emails as before, that total opens remained the same at first then slowly trended up, while “the raw number of clicks is 5% higher than it was at the same time last year.” Presumably, the fewer disinterested recipients, the more likely your email is prioritized in the remaining subscribes’ inboxes. That success made them build strict rules: If a subscriber doesn’t open or click a link in at least one out of every 16 emails, they are marked as unengaged.

Leadpages found something perhaps more troublesome than simply deadweight subscribers. In a survey of a thousand people in 2016, only 40% of people said they unsubscribe from emails they don’t want to receive. The remainder? 9% said they mark unwanted newsletters as spam.

If more than 0.3% of your subscribers marks your email as spam, Gmail may start automatically doing the same. That, perhaps, is the best reason to bulk-delete people who don’t appear to be reading your emails. Better to accidentally excise a fan than to risk a subscriber triggering Google’s wrath.

The case for keeping “dormant” subscribers on your lists

If only it were that simple.

For email tracking, today, is more of a cat-and-mouse game than a science. Email tracking has a fairly straightforward history: When you load an image from a server, your browser sends a bunch of data about your computer, and devs figured out in the ’90’s that they could put a tiny, one-pixel image in emails and get the same analytics. Then the EFF said such tracking was controversial at best, unethical at worst, the EU required informed consent for tracking pixels, and most email apps started blocking images by default.

Which means your email open rates today are likely not at all your actual email open rates. Apple Mail pre-loads images, so every subscriber will appear to have read your email. Outlook loads no images, giving you the opposite effect of seemingly zero readers. Gmail loads the images from random servers, muddying the data. Open rates are looking through a glass darkly, at best.

Click rates are a better—but still faulty—metric. In the best of circumstances, you can add a unique UTM to URLs in emails and match each click to a real subscriber. In reality, it’s entirely possible for the UTM to get trimmed, or for a perfectly engaged reader to be happy reading from their inbox and never click through to your site.

Replies are a much better email metric, and they’re as likely to come from those who click links as from those who read only in their inbox. They’re also, perhaps, most likely to come from either your superfans or detractors, both of whom are more likely to take the time to write than a moderately happy yet busy reader.

That’s why you might not actually have to prune your list so deeply. As long as you’re using a tool like Buttondown that can automatically clean up your list and remove the broken, malicious, and complaint-sending email addresses, it’s ok to leave what otherwise looks like lurkers on your list. At best you’ll remove real readers; at worst, you’ll leave the people who hate-click, and increase the likelihood of getting your emails marked as spam.

Don’t overprune

“When pruning, the basic rule of thumb is that less is more,” writes Benjamin Kilbride about husbandry in a modern take on The Old Farmer’s Almanac. “Don’t prune recklessly.”

What goes for landscaping goes for lists as well. Follow the rule of thirds; trim no more than 30% of a tree (or so the internet says, but please don’t take my word for it, I’ve killed cacti). For email, you can’t kill an email list by cutting too much, per se, but you can run the risk of keeping someone who likes your emails from reading. When open and click rates tell at best part of your readership story, you risk cutting your faithful-yet-silent readership by pruning your list too deeply.

So don’t prune recklessly. If you’re truly concerned about your list’s dead weight, segment your list. Everyone who’s either opened, clicked, or replied in the past six months or year stays on your core list. Send everyone else an email, asking for them to reply if they’d like to stay on your list. Move anyone who replies back to the core list, then perhaps repeat once more for those who missed the first message. You can do that manually, or automatically email people subscribers who go dormant. It might be a step too far for carefully built, organic newsletter audiences who weren’t auto-opted-in and didn’t enter their email just for a lead magnet, but it can be a way to clean up more messy, dated lists for a stronger foundation.

Then, over time, keep your email audience engaged. Ask, occasionally, for your readership’s thoughts and ideas, for a better handle on your readership’s engagement melded with a bit of community building. Resist the urge to boost subscriber numbers quickly with low-effort giveaways; consider doing pop-up newsletters for one-off events and topics out of your traditional purview to keep your list’s focus clear. And leave tools like Buttondown’s subscriber cleanup and signup form captchas enabled, to ensure you’ve got mostly well-intentioned humans on your member roll.

Then keep writing, without obsessing either over your total subscriber numbers or potential dead weight. Pruning’s good in spring; the remainder of the year, you’re better off honing your craft and sending the newsletters that keep people coming back for more.