How does history of sender activity affect scoring?
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Think of your sender reputation like a credit score. A long record of on-time payments means one missed payment doesn't tank everything. But if you've defaulted before, lenders remember. ISPs and mailbox providers work the same way.
Every time you send email, the receiving infrastructure is quietly updating your profile. Spam filters track complaint rates, bounce rates, engagement signals (opens, clicks, deletions, marking as spam), and whether your domain and IP pass authentication checks consistently. All of this builds a picture of what kind of sender you are.
How far back do ISPs actually look? Most major mailbox providers weight the last 30 to 90 days most heavily. Gmail is known to look at rolling 30-day windows for many of its scoring signals. Outlook tends to hold longer memory, especially for domain-level reputation. That said, positive signals decay faster than negative ones. A clean month won't fully erase a bad quarter.
New senders face the toughest version of this. With no history, filters have nothing to calibrate against, so they apply conservative defaults. That's the core reason domain warming and IP warming exist. You're not just avoiding spam traps. You're building a track record from scratch.
What if your history is messy? Rebuilding takes time, and there's no shortcut. Here's what actually moves the needle:
- Start sending to your most engaged subscribers only. High open rates tell ISPs you're turning a corner.
- Keep volume low and consistent while you rebuild. Sudden spikes read as suspicious even if the content is clean.
- Fix whatever caused the problem. If it was a bad list, clean it. If it was authentication gaps, close them. Filters will notice the improvement over time.
- Expect 60 to 90 days of steady clean sending before you see meaningful reputation recovery at most major providers. Some, like Outlook, can take longer.
One thing that trips people up: switching to a new IP or subdomain doesn't wipe the slate clean if your domain reputation is already damaged. The domain carries its own history separately from the IP. Starting fresh on infrastructure while keeping a tarnished domain doesn't help as much as senders hope.
If you're not sure where your reputation stands right now, you can check whether your domain or IP has landed on any blocklists with our free Blocklist Checker. And if you're actively trying to dig out of a reputation hole, our SOS hotline is free to use (no pitch, just help).
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