I'm surprised there aren't companies that look at the expiration dates of SSL certificates and try and get them to use their service to get a new one, like domain people do. Seems like it could also be a feature of New Relic / Pingdom / etc.
[Errno 1] _ssl.c:504: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failedAlso, if you check SSL cert validity, you should totally advertise that! I remember I've been paying for one such service where they would monitor SSL url, but would not alert you about SSL cert expiration. I found out the hard way.
The advanced (paid) functionality is a restart of your vps or other automatic ssh action trying to recover it when it's down.