My MUA (email client) is Gnus, which runs under Emacs. I migrated to it from Mutt many years ago because of the level of flexibility it offers.
It also has integration with other important packages. For example, cross-references can be stored using Org mode, which I use frequently in my notes to reference messages and threads.
I've gathered nearly 1 million messages (I subscribe to many lists) over the years, and get many 100s a day, and it manages them well.
@mikegerwitz What’s the size of your ~/News folder? Which back‑end do you use for email—nnmaildir? Do you use Gnus in offline mode?
@kmicu Those were going to be the subject of future posts, but in summary: I use a local IMAP server which aggregates mail from a couple of different sources using fetchmail. It stores messages in a maildir, but Gnus connects to the IMAP server. My maildir is just under 10GiB; nearly all my mail is plain text.
This is really out of date, and I really should get to updating it, but here's my config (as of that time) in a literate Org file. I no longer use offlineimap.
@kmicu So it's offline in the sense that fetchmail is the only thing connecting to the Internet, so I'm able to use Gnus without an Internet connection.
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