I've been using mailcrypt for years, but someone recently pointed out
that MIME is now the "standard" way to do signing. Fair enough, I'd be
happy to make the messages look a little less awkward in
non-encryption aware readers anyway.

So I'm trying to switch to PGG. I've removed all the mailcrypt stuff from
my .gnus file and replaced it with:

;; PGG
(require 'pgg)

(setq pgg-cache-passphrase t)
(setq pgg-passphrase-cache-expiry 3600)

;; Emacs should always decrypt and verify emails automatically
(setq mm-verify-option 'always)
(setq mm-decrypt-option 'always)

;; Automcatically sign when sending mails

(defun will-you-sign ()
  (interactive)
  (if (y-or-n-p "Do you want to sign this message? ")
     (mml-secure-message-sign-pgpmime)))

(add-hook 'gnus-message-setup-hook 'will-you-sign)

In a few minutes I'll probably get around to replacing will-you-sign with
sign-always, but that isn't the issue.

With the setup above, using Gnus 5.10.2, when I send a signed message,
it asks me for my key three times in a row (apparently once for each
destination that the message goes to, the outside world, the current
group, and the monthly archive group).

What's more, if I send another message right away, it asks me three
times again. It appears not to be caching the passphrase.

Clues, please?

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | The years teach us much which the days
http://nwalsh.com/            | never knew.-- Emerson