The Re-Engagement Campaign Playbook

Defining "Inactive"

Before you can re-engage inactive subscribers, you need a clear definition of what "inactive" means for your list. The standard benchmark is no opens and no clicks in the last 90 days, but the right threshold depends on your sending frequency.

• Daily senders: 60 days of no engagement is a strong signal of inactivity.
• Weekly senders: 90 days (roughly 12 missed emails) is a reasonable threshold.
• Monthly senders: 120-180 days may be more appropriate since subscribers have fewer opportunities to engage.

Use your own engagement data to calibrate. Look at the distribution of "days since last engagement" across your list. You'll typically see a natural break point where engagement drops off sharply — that's your inactivity threshold.

One important caveat: Apple Mail Privacy Protection inflates open rates by pre-loading tracking pixels. If a large portion of your list uses Apple Mail, rely on clicks rather than opens to identify truly inactive subscribers.

Why Inactive Subscribers Hurt You

It's tempting to keep inactive subscribers on your list because they inflate your subscriber count. But keeping them actively damages your email program in several measurable ways:

Sender Reputation Decay

ISPs like Gmail, Yahoo, and Microsoft track your engagement rates at the domain and IP level. When a large percentage of your sends go to subscribers who never open or click, your overall engagement rate drops. ISPs interpret this as a signal that your content isn't wanted, and they begin routing more of your emails to spam — including emails to your engaged subscribers.

Spam Trap Accumulation

Email addresses that have been abandoned are sometimes recycled by ISPs as spam traps. If you're sending to addresses that haven't engaged in years, some of them may now be spam traps. Hitting a recycled spam trap tells ISPs you're not maintaining your list hygiene, which is a direct reputation hit.

Cost Inflation

If your ESP charges per subscriber or per send, inactive subscribers are a direct cost with zero return. A list of 100,000 where 30,000 are inactive means you're paying 30% more than you should for zero additional value.

The 3-Email Re-Engagement Series

A structured re-engagement campaign gives inactive subscribers a clear opportunity to re-engage before you remove them. Three emails, spaced 5 days apart, is the most common and effective pattern.

Email 1: "We Miss You" (Day 0)

The first email is a gentle reminder of the value you provide. It should feel warm, not desperate.

• Subject line: "Still interested in [your core value proposition]?"
• Content: Remind them why they subscribed. Highlight your best recent content or product updates they've missed. Include a single, clear CTA — "See what's new" or "Read our latest guide."
• Tone: Friendly and value-focused. Don't mention that they've been inactive — focus on what they're missing.
• Send to: All subscribers who meet your inactivity threshold (e.g., 90 days no engagement).

Email 2: "Last Chance" (Day 5)

The second email escalates slightly. Consider offering an incentive or exclusive content to motivate action.

• Subject line: "A special offer, just for you" or "We put together something exclusive"
• Content: Offer something of genuine value — a discount code, an exclusive piece of content, early access to a feature, or a free resource. Make it clear this is a limited or exclusive offer.
• Tone: Generous but with a subtle hint that this is a special effort to reconnect.
• Send to: Subscribers who didn't engage with Email 1.

Email 3: "Goodbye" (Day 10)

The final email is transparent about what's happening. This is your most important email because it creates urgency and gives subscribers a clear choice.

• Subject line: "Should we stop emailing you?" or "We're cleaning our list — want to stay?"
• Content: Be direct: "We haven't heard from you in a while. We want to make sure we're only sending emails to people who want them. Click below to stay on our list, or do nothing and we'll remove you automatically in 7 days."
• CTA: A prominent "Keep me subscribed" button. Make it impossible to miss.
• Tone: Respectful and transparent. No guilt-tripping. Frame it as cleaning up, which it is.
• Send to: Subscribers who didn't engage with Email 1 or Email 2.

The Sunset Policy

Anyone who doesn't engage with any of the three re-engagement emails should be removed from your active sending list. This is your sunset policy, and it's the most important part of the entire process.

Suppress, Don't Delete

Move unengaged subscribers to a suppression list rather than deleting them entirely. There are two reasons:

• Compliance: GDPR and CAN-SPAM require you to honor unsubscribe requests. If you delete a contact and they somehow re-enter your system (via a new signup form), you might email them in violation of their previous opt-out. A suppression list prevents this.
• Re-acquisition: If a suppressed subscriber later visits your website and actively re-subscribes through a form, you have fresh consent and can add them back to your active list.

Frequency

Run your re-engagement campaign on a rolling basis — quarterly is ideal for most senders. Some teams run it monthly if they have high subscriber acquisition rates. Don't wait for a "spring cleaning" once a year; by then, the deliverability damage from inactive subscribers has already accumulated.

Measuring Results

After running a re-engagement campaign, track these metrics:

Reactivation Rate

The percentage of inactive subscribers who engaged with at least one of the three emails. A typical reactivation rate is 5-15%. If you're above 15%, your inactivity threshold might be too aggressive — you're catching subscribers who were just temporarily quiet. If you're below 5%, the threshold might be too generous, or your re-engagement content needs work.

Deliverability Impact

Track your overall inbox placement rate (via tools like GlockApps or Google Postmaster Tools) before and after removing inactive subscribers. Most senders see a measurable improvement in inbox placement within 2-4 weeks of a list cleanup. This is the clearest evidence that inactive subscribers were dragging down your reputation.

Engagement Rate Improvement

Your overall list engagement rates (open rate, click rate) should increase after removing non-engagers, since you've removed the denominator drag. This isn't just a mathematical artifact — it reflects better ISP reputation and higher inbox placement for your remaining subscribers.

Cost Savings

If you're on a per-subscriber pricing model, calculate the direct cost savings from removing inactive contacts. For a list of 50,000 where 15,000 are removed, the savings can be substantial — potentially hundreds of dollars per month depending on your platform.

Common Mistakes

• Sending re-engagement emails that look like regular emails. Your re-engagement emails need to stand out. Use a different design, a different tone, and a clear CTA that's distinct from your regular content.
• Not actually removing people who don't re-engage. The whole point of this exercise is list hygiene. If you run the campaign but keep everyone anyway, you've wasted the effort and the subscribers' time.
• Running the campaign once and never again. List hygiene is ongoing. Set up a recurring automation that feeds subscribers into the re-engagement flow as they cross the inactivity threshold.
• Offering discounts to everyone in Email 1. Training subscribers that going silent earns them a discount is a dangerous precedent. Save incentives for Email 2 at the earliest, and consider non-monetary incentives first.