Sorry, but unless I can manage my email with sensible rules, I'm not going to manage it.
I need to be able to have rules that let me move email automatically after it's been read or after it's been in the Inbox for some time. But that's not really possible with most server side rules engines (they only look at mail when it arrives), client side rules engines are dead and I don't use email from a fixed desktop machine anyway, and I'm not going to write an imap based filtering engine (I did it once on company equipment, and it wasn't fun enough to do it again).
If you need more inspiration, I used to use Pegasus Mail, and I'd have a small number of filters on Inbox open: there were some lists I was on that didn't need to ever be in the inbox, and most of my filters on Inbox close: move read or timed out mail into folders it belonged; read mail with no other rule would end up in Archive/YYYY-qQ; I found quarterly was the best granularity, monthly archive folders were too fiddly. But modal flow like that isn't very current.
Pegasus Mail was very good when it owned the mail (pop3), and works ok with a competent IMAP server, but work switched to Exchange and it was very slow, and Pegasus didn't work well with a slow IMAP server. That was the start of my slide into inbox 40k :(
I need to be able to have rules that let me move email automatically after it's been read or after it's been in the Inbox for some time. But that's not really possible with most server side rules engines (they only look at mail when it arrives), client side rules engines are dead and I don't use email from a fixed desktop machine anyway, and I'm not going to write an imap based filtering engine (I did it once on company equipment, and it wasn't fun enough to do it again).
So Inbox 40,000 it is.