Except they've *not* expired. If I've not looked at, opened or in any way otherwise interacted with any RSS applet or application, why should articles be considered expired?

They should expire in one of two situations:

1) I've read them and didn't tick "Save for later"
2) They've been deleted/expired from the upstream feed.

Expiring on automated update is just plain broken, and I've yet to here anything *close* to a reasonable argument that it's not. Where's the UCD here?

1) Broken quoting.
2) Usage of HTML components for plain text emails.
3) Slow.
4) ...

There's lots more, but really I couldn't tell you anymore. I've not used it since OS 2005.

There's no point defending it either, Nokia have realised it's broken or they wouldn't be investing in Modest & Tinymail!