How often should I run inbox placement tests?
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You've just finished building a campaign you're really proud of. The subject line is sharp, the content is solid, the list is clean. But how do you know it's actually going to land in the inbox before you hit send to 50,000 people?
That's what inbox placement testing is for. And how often you should run it really depends on where you are in your sending cycle.
Before major campaigns, always test. If you're about to send to your full list, a suppressed segment, or anything with high stakes attached to it, test first. This isn't optional. A test run before a big send can catch a deliverability problem you'd otherwise only discover in your open rate data three days too late.
After any infrastructure change, test immediately. Switching ESPs, moving to a new IP address, updating your authentication records (SPF, DKIM, DMARC), or making significant template changes? All of those can affect where your email lands. Don't assume it's fine. Test.
For steady-state sending, monthly or bi-weekly works well. If your sending volume and content haven't changed much, you don't need to test every single send. A regular check-in every two to four weeks gives you a baseline and helps you spot gradual drift before it turns into a real problem.
When engagement drops unexpectedly, test right away. If your open rates fall off a cliff without an obvious reason, inbox placement is one of the first things to check. A drop in engagement can mean fewer people are seeing your email at all, not that they've lost interest.
High-volume senders (daily sends, large lists) benefit from continuous monitoring tools that track placement across providers like Gmail, Outlook, and Yahoo Mail on an ongoing basis. For lower-volume senders, that level of tooling is often overkill. Consistent pre-campaign checks plus a monthly baseline test covers most situations.
Once you have results, you'll want to know what to do with them. Check out how to interpret placement percentages so a number like "72% inbox" actually tells you something useful.
Not sure where to start with placement testing? Our SOS hotline is free and we'll point you in the right direction without the pitch.
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