How often should lists be cleaned according to M3AAWG?
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M3AAWG (the Messaging, Malware and Mobile Anti-Abuse Working Group) is the industry body that sets anti-abuse best practices for email senders. Their list hygiene guidance is worth knowing because mailbox providers actively follow their recommendations when deciding what counts as responsible sending.
Their stance on cleaning frequency comes down to two layers working together.
The first layer is real-time, every single send. Every time you send, your system should immediately suppress hard bounces, process unsubscribe requests, and remove addresses that generate spam complaints. There's no waiting period for these. A hard bounce means the address is gone. A complaint means that person doesn't want your mail. Both need to come off your active list before the next send, full stop.
The second layer is periodic review. M3AAWG points to quarterly or semi-annual audits where you look at the bigger picture. That means checking where your subscribers came from (source quality), how long addresses have been sitting without opening anything, and whether certain acquisition channels are producing addresses that bounce or complain at higher rates than others. These audits aren't about re-running the same bounce sweep. They're about spotting patterns you can't see send-by-send.
How often you need those deeper reviews depends on how fast your list moves. A list growing by thousands of addresses a week needs closer attention than one that's stable and well-maintained. Faster growth means more chances for bad addresses to slip through, so you'd want to audit closer to quarterly. A slower-moving list that's been well managed could reasonably go six months between full reviews without much risk.
The practical takeaway is that "continuous" doesn't mean running a full audit every day. It means your bounce and complaint handling is automated and immediate, and your bigger pattern reviews happen on a real schedule rather than whenever someone remembers.
If you want to run a clean on your list before your next quarterly review, we can help with that at RME Clean. Or if you're not sure what you're looking for in a list audit, our SOS hotline is free.
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