A system of this kind depends on regular review of the messages that pass through the filters, of course. But that review is a simple matter of checking @INBOX. Any message that is currently unread, flagged, or parked in the mobile Review folder shows up in @INBOX, and its presence there is a reminder to me that I need to deal with it. A recurring OmniFocus task reminds me to review messages that may be awaiting my attention; but if you use email as much as most people do, you'll always be aware of what's sitting there.
The goal is to keep @INBOX empty. If mine ever scrolls onto a second page, that's a sign that I've waited too long to deal with things. At that point I ask myself whether each item is something I'll ever get to. If the answer is "Eventually," I make a task for it and clear it from @INBOX. If the answer is "Probably not," I unflag it, mark it as read, and let it float away.
Even though my @INBOX is empty, I have a fully searchable archive of every message I haven't intentionally deleted. My system didn't require any extra filing, tagging, or additional processing. GMail search is especially fast and accurate. When I need to find a long-gone email, I load up MailPlane or GMail on my iPhone and quickly locate whatever the moment calls for.
The result is an empty inbox and true peace of mind. The system is easy to maintain moving forward. The filters take care of half the work, and I can apply the process as time allows. Best of all, I can rest easy at night knowing that I won't wake up in the morning to hundreds of unread messages clamoring for my attention.
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