I think you're trying to solve a non-problem since the company that sells the certificates warns you (sometimes even more than those intervals), afterall, they want you to renew as well. As for checking for quality, that should be the sys admin task or the webmaster. good luck though!
CAs won't alert you if someone breaks into your server and replaces your certificate. They won't alert if you if you accidentally push a config change and start serving the wrong certificate to customers... And they certainly will not alert you if you are using a revoked certificate in production.
I've bought multiple certificates from different reputable vendors - I only ever got one Heartbleed notice. (This pattern repeats itself)
Many shops don't have a dedicated admin / webmaster auditing their certificates and even those that do have had public issues (Akamai, Apple, GitHub, Stripe...etc)
The value in a service like Snitch is that we worry about your SSL certificates. Many people don't have the interest or time in rolling their home grown monitoring of this stuff...