Email deliverability isn’t a “set it and forget it” game. If you want your emails to keep landing in the inbox, you have to keep email warming going—not just before a big campaign, but all the time.

Most people think warming up an email address is just a one-time process:

👉 Warm up a new domain for a few weeks.

👉 Start sending emails.

👉 Enjoy good deliverability.

But what happens after a few weeks? Your deliverability drops. Your emails start getting ignored, engagement declines, and eventually, spam filters catch on. Before you know it, your inbox placement tanks, and you're left wondering what went wrong.

Let’s break down why ongoing email warm-up is the key to keeping your emails in the inbox—permanently.

1. Email Deliverability Naturally Declines Over Time

Even if you’re doing everything right, your deliverability isn’t static. It either improves or declines based on how email providers (like Gmail and Outlook) view your engagement levels.

• If engagement is high (opens, replies, clicks) → You stay in the inbox.

• If engagement is low (ignored emails, spam reports, low open rates) → You slowly slide into spam.

It happens gradually—so at first, you might not notice. But after a few weeks of no warm-up, open rates start dropping, replies slow down, and suddenly, your emails aren’t reaching inboxes anymore.

💡 Ongoing warming prevents this decline by maintaining steady, positive engagement.

2. Warming Up Only Before a Campaign Isn’t Enough

A lot of people think, “I’ll warm up my email for a few weeks, then I’ll be good to go.” Nope. That’s a myth.

Here’s why this approach fails:

❌ You warm up your domain, send your first few campaigns, and everything looks great.

❌ But then, your ratio of emails sent to engagement drops—because let’s be real, not everyone loves your emails enough to reply or click every time.

❌ With less engagement, inbox providers start doubting your sender reputation.

❌ Within a few weeks, you’re back in the spam folder.

This is why warming up only before a campaign isn’t enough—you have to keep warming your email account to balance out the natural dips in engagement.

3. Spam Filters Need Constant Positive Signals

Spam filters don’t just look at how many emails you send—they look at what happens after you send them.

• Do people open them?

• Do people reply?

• Do people move them out of spam?

• Do people mark them as important?

When you always keep email warming active, it creates ongoing positive interactions—moving messages from spam to inbox, generating opens, and mimicking real human engagement. This teaches inbox providers to trust your emails.

💡 Every single day your emails land in spam and get manually pulled back to the inbox, spam filters take note. This tells them, Hey, this sender is legit. Let’s stop filtering their messages.

4. Keeping Email Warm Balances Your Reputation

Think of email reputation like a credit score. If you don’t use credit cards for months, your credit history weakens. The same happens with email deliverability.

If you stop warming your inbox:

📉 Your engagement rates drop

📉 Your reputation weakens

📉 Your deliverability declines

💡 Keeping your email warm is like consistently making small, on-time payments—it keeps your reputation strong.

5. Inbox Placement is a Long-Term Game

Getting into the inbox once doesn’t mean you’ll stay there forever. Email deliverability is a long-term game, and inbox providers constantly evaluate whether you deserve to be there.

By continuously warming your email, you make sure that:

✅ Your engagement rate stays steady.

✅ Your reputation remains strong.

✅ You’re always sending positive signals to spam filters.

Inbox placement isn’t a one-time win—it’s a constant battle. Ongoing warm-up is your secret weapon.

6. How to Keep Your Emails Warm (And Out of Spam)

Okay, so we’ve covered why email warming should never stop—but what does that actually look like? Here’s how to do it right:

1. Use an Automated Warm-Up Tool

Manually warming up an email is time-consuming. Instead, use an automated tool that mimics real engagement—sending emails, getting replies, and moving messages from spam to inbox 24/7.

2. Keep a Consistent Sending Pattern

If you send huge bursts of emails and then go silent for weeks, spam filters notice. Keep a steady, consistent email volume.

3. Monitor Your Deliverability Metrics

Watch your open rates, bounce rates, and spam complaint rates.

If engagement starts to dip, it’s a warning sign that you need to ramp up warm-up efforts.

4. Keep Your Email List Clean

Bad email lists = spam folder nightmares. Remove inactive subscribers regularly to prevent high bounce rates and low engagement.

Final Thoughts: Never Stop Warming = Never Stop Landing in the Inbox

Inbox providers love engagement. The moment your engagement drops, your deliverability starts declining.

The good news? You can fight back.

🚀 By continuously warming your email, you maintain engagement, boost reputation, and teach inbox providers that your emails belong in the inbox—not in spam.

Don’t make the mistake of thinking warm-up is a one-time thing. The senders who win at email deliverability in 2025 will be the ones who never stop warming.