I’ve seen companies watch their campaigns flatline, not because their product wasn’t compelling, but because their email list was silently decaying. The signs can be so subtle that you often don’t realize it until the damage is done.
Just ask Gene Massey, founder and CEO of MediaShares and a customer of my company, ZeroBounce. His business relies on email to connect with investors. But after getting a 12 percent bounce rate, the entrepreneur found himself unable to send any emails at all: His email service provider had shut down his account. To get it reinstated, he had to clean his list and remove all the invalid addresses to get bounces under control.
His story is a reminder that an email list isn’t permanent. It needs care. And Massey is not the only one. Many companies don’t realize their list is failing until they see the fallout.
So, how do you know if your list is outdated and risky? Beware of these warning signs:
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1. Your bounce rate keeps getting higher
If it’s higher than 2 percent, it’s a sure sign your list has accumulated too many obsolete contacts. Mailbox providers take note of your bounces and can start filtering your emails out of your customers’ inboxes and into the spam folder.
2. Engagement is flatlining
If your open and click rates are declining month after month, you need to take action. A healthy list shows consistent signs of life: people opening, clicking, and replying. When those numbers stall, it’s often because many of your contacts are inactive.
3. You’re seeing more spam complaints
If subscribers who once opted in are now hitting “report spam,” it may be a sign your list is outdated or misaligned with your audience’s current needs. Another reason could be that those prospects didn’t opt in to get your emails.
4. You have too many generic sign-ups
Addresses like info@company.com or sales@company.com are often shared by a group of people who may ignore or delete your emails. Having too many contacts who don’t engage tells mailbox providers that your content is irrelevant.
5. Your emails are going to spam
If your emails skip the inbox entirely, it’s probably a combination of factors, but the health of your list plays an important role. Once you’re in the spam folder, climbing out is tough.
How to bring your list back to life
Fixing your list isn’t complicated; it just takes discipline:
Ask permission. Make sure everyone on your list has opted in to get your emails. This approach helps you avoid spam reports and build a more engaged list.
Regularly clean your list. Even good emails go bad over time. Make a habit of pruning expired contacts every quarter.
Re-engage dormant subscribers. They bring your metrics down, so you can’t ignore them. Run a reactivation campaign before removing inactive prospects.
Bonus tip: Watch out for bots
In 2025, bots are smarter than ever. They generate fake signups that look real until you try to email them. Add them to your list and you’ve got a silent killer of deliverability.
Gene Massey says: “Sometimes we get fake and bot sign-ups. There are so many bots out there now. You need to verify that address because you don’t know if it’s real or if that signup came from a bot.”