Heh. I wrote 3 calendar reminders 60, 30 and 15 days out for our engineering team on Friday reminding us to do this when the time comes. Now, I will reserve the right to feel smug.
Yeah, I mean, if you're responsible for an SSL cert, why isn't this common practice. I'm going to join you in smugness, because I did this as well on a web app I was partially responsible for. It's super easy, and if your system is at all critical (mine wasn't even, really - it was an internal-only wiki with a self-signed cert from a different internal team), then there's no excuse not to.
There was a bit of jest in the smugness, but in my case it was because I inherited the SSL responsibilities from an outgoing engineer and randomly thought to myself "I wonder when these servers certs expire?". It's the type of thing that multiple people need to keep an eye out for, not just one person in the event of inevitable turnover. For something that can entirely take down your site/service for an indeterminate period of time that is entirely out of your control, it's a necessary evil.