A sunset policy is the rule for when you stop mailing people who stopped reading. It feels like shrinking your asset; it’s actually maintenance on it.
Why quiet subscribers cost you
Mailbox providers grade you on engagement ratios, not raw reach. Every send to someone who ignores you dilutes your open and click rates, and providers read sustained low engagement as “this sender’s mail isn’t wanted”—then file you accordingly for everyone, including the people who love you. It gets worse with time: abandoned mailboxes decay into bounces, some are reclaimed as spam traps, and a recipient who forgot subscribing is a spam complaint waiting for a bad morning. The unengaged tail isn’t neutral; it’s a slow leak in your domain reputation.
The policy that works
- Pick the line. The generally accepted standard: recipients with no open or click in the past six months leave your regular marketing sends. Adjust for your cadence—a daily sender can sunset sooner; a quarterly one, later.
- Try one honest re-engagement. A short “still want these?” campaign—ideally with topic-level choices so “less” is an option, not just “none”. Whoever clicks stays.
- Let the rest go. No response means the answer was no. Remove them from marketing sends (transactional mail they trigger is fine). Sending to someone who hasn’t engaged in a year isn’t persistence, it’s noise with a complaint risk attached.
Automate the boring parts: engagement-filtered segments make the policy self-executing, and bounce/complaint webhooks plus your suppression list handle the involuntary exits.
The mindset shift
List size is a vanity metric; engaged list size is the operational one. A 10,000-person list where 9,000 read you outperforms a 100,000-person list where the same 9,000 read you—same revenue, radically better reputation. Sunsetting isn’t losing subscribers you had; it’s admitting you’d already lost them, before the mailbox providers bill you for the pretense.