The 22.5% Attrition Rule
Data is not static. In the B2B world, it is highly volatile. Studies consistently show that B2B email databases decay at a rate of approximately 22.5% per year. This means if you have a list of 10,000 subscribers today, and you do nothing to maintain it, 2,250 of those emails will bounce one year from now.
The reasons for this churn are structural:
- Employee Turnover: The average tenure of a tech employee is under 2 years. When they leave, their inbox is deactivated.
- Company Mergers/Failures: Companies go bust or get acquired, changing their domain structures.
- Role Changes: People move departments and get new aliases.
The Cost of Inaction
Many marketers believe they can just "clean as they go," removing bounces after they happen. This is a flawed strategy. By the time you receive the bounce, the damage is done. You have already wasted a send credit, skewed your analytics, and potentially triggered a spam alert if the bounce rate on a single campaign exceeds 3%.
Implementing a Sunset Policy
To combat decay, you need a proactive "Sunset Policy" supported by verification:
- Identify Unengaged Users: Users who haven't opened an email in 6 months are high risk. Their inbox might be dead, but the server hasn't bounced yet (soft bounce).
- Batch Verify: Run this segment through EmailVerifierAPI.com.
- The Purge:
- If the API returns
invalid: Delete immediately. Do not try to re-engage. - If the API returns
valid: They are real, just ignoring you. Move them to a re-engagement campaign.
- If the API returns
Regular verification is the only way to arrest the natural entropy of your database. It keeps your Sender Score high and ensures your marketing metrics reflect reality, not a graveyard of dead leads.