As noted previously, I’ve opted to serve all of my sites securely. I even went to far as to get ethitter.com on Chrome’s preload list, meaning no major browser even attempts an insecure connection to my site. Try loading http://ethitter.com/ in Chrome, Firefox, or Safari, and the browser will redirect to https://ethitter.com/ before my nginx configuration ever tells it to.
That vaguely-entertaining detail aside, this means that I’ve reason to be concerned about how soon my SSL certificates expire. The HPKP headers I set have 60-day lives, which I need to account for any time I renew the certificate for a pinned domain.