How do you handle system maintenance during a crisis?

Back in the mid-1990s, a particular vendor's training classes that I was taking always began the same way: "It's not IF a failure is going to happen, it's WHEN." It's annoying to have someone repeat this mantra, no matter how true it is, at the beginning of every class. It develops an unhealthy paranoia about hardware, software, and careless sysadmins. It also helps sell more classes but that's another story.

Yes, failures are going to happen. Yes, they're terrible. Yes, you'll be up all night dealing with the incident, the questions, and the irritating "advice" that comes with trying to troubleshoot a problem while on the phone with two dozen people—most of whom haven't a clue of what's really going on. That also is another story. This particular story focuses on how you handle support during a crisis.

A crisis can be anything from an unfortunately timed vacation to a weather-induced power outage to a global pandemic. You need to be prepared for a crisis because it's not if a failure is going to happen, it's when. So, the question is, "How do you handle system maintenance during a crisis?"

Having "been there and done that," I feel infinitely qualified to offer up this poll to find out how others handle crises. I'd like your feedback to help better understand what the current trends are.