Send only to people who asked for your mail, avoid pre-checked sign-up boxes, never buy lists, make unsubscribing easy and honor it fast, and increase volume gradually. Google's sender guidance ties these habits to spam complaints, which drive reputation and delivery.
Definition
List hygiene is the set of habits that keep your recipient list made up of people who want your messages. Consent hygiene is the record keeping that shows how and when each person agreed. Together they reduce spam reports, which mailbox providers use to judge you.
What Google's guidance says to avoid
Google's guidance lists these sending practices to avoid: purchasing email addresses from other companies, and sending messages to people who did not sign up, since those recipients may mark your mail as spam and future messages to them will be marked as spam. It also says to avoid opt-in forms that are checked by default and automatically subscribe users, and notes that some countries restrict automatic opt-in, so check the rules in your region.
It adds that if you manage mailing lists, you should send only to people who want the mail, and that frequent spam reports against your domain make future messages more likely to be marked as spam.
A hygiene checklist
| Habit | Why |
|---|---|
| Unchecked opt-in boxes | Avoids automatic subscription |
| Confirmation of new sign-ups | Reduces typos and fake addresses; some teams use a confirmation email |
| Unsubscribe link in every marketing message | Gives a better exit than the spam button |
| One-click unsubscribe for bulk marketing | Required by Google for bulk senders |
| Honor opt-outs quickly | The FTC guide says within 10 business days for US commercial mail |
| Remove bounces and long-inactive contacts | Protects reputation |
| Steady, gradual sending | Avoids bursts that trigger limits |
| Segment by engagement | Start campaigns with engaged users |
Steps
- Audit every sign-up form for pre-checked boxes and change them to unchecked.
- Record consent: timestamp, source form, text shown. See consent record fields.
- Add one-click unsubscribe headers to marketing mail. See how it works.
- Propagate unsubscribes to every system that sends, including partners. See consent withdrawal across systems.
- Ramp new lists slowly and watch the spam rate. See spam rate targets.
- Review inactive contacts every quarter and remove those who no longer engage.
Where this meets security
Poor list hygiene is also an abuse path. Sign-up forms that email any address typed into them can be used to send unwanted mail to strangers. Confirmation messages should be short, contain no promotion, and be rate limited per address and per IP.
Where Safeguard fits
Safeguard's compliance and evidence automation helps teams keep consent and retention policies documented and checked. This post is general information, not legal advice. The free scan is at https://gold.safeguard.sh/scan.
Quick check
Is double opt-in required?
Not by the sources used here. Confirmation can reduce bad addresses, and some regions have their own rules, so check where your recipients live.
Can I email a purchased list once?
Google's guidance says not to purchase addresses, since recipients who did not sign up may report spam.
Sources
- Email sender guidelines, Google Workspace Admin Help
- CAN-SPAM Act: A Compliance Guide for Business, FTC
Last reviewed: 19 October 2026.
