With it I can
autossh -M50000 -t -D1080 -Nf crashingdaily.com
to keep a seemingly persistent SOCKS proxy running.
autossh -M50000 -t crashingdaily.com 'screen -aAdR autossh'
to maintain an interactive session.
The value that I missed earlier is that the connections are maintained (re-established, actually) even if I change networks – which my laptop and I often do.
Jon’s View has a nice posting on using autossh for SOCKS proxying.
And Dread Pirate PJ has a good instruction for combining autossh and screen for persistent interactive sessions.