Six months, 10,000 emails, and a lot of bounces

We wanted to know what actually happens to B2B emails over time, so we ran an internal study. We took 10,000 verified business emails — all confirmed deliverable at the start — and tracked them for six months without any maintenance. No hygiene passes. No verification refreshes. Just watching what broke.

Month one: 98.4% deliverable. Fine. Nothing to worry about. Month three: 94.1%. Starting to feel it. By month six: 89.7%. More than one in ten emails that were good six months ago were now either bouncing or soft-failing.

The breakdown was interesting. About 60% of the bounces were hard bounces — the email address literally didn't exist anymore. Person left the company, company changed their email format, domain expired. The other 40% were soft bounces — mailbox full, server temporarily down, message blocked. Some of those would recover, but most wouldn't.

Industry made a difference. Tech company emails degraded fastest (about 13% over six months). Government and education were slowest (about 7%). The pattern tracks with job mobility — people in tech just move around more.

The real cost isn't the bounces themselves. It's what happens when your bounce rate creeps past 2-3%. Email providers start throttling you. Your domain reputation takes a hit. Campaigns that should land in inboxes start landing in spam. Your marketing team blames the copy. Your sales team blames the list. Nobody looks at the data decay.

The fix is boring but effective: verify before every major campaign. Suppress bounces immediately. Run a full hygiene pass quarterly. It's maintenance work, but the alternative is slowly training email providers to distrust your domain.