Most outages don't come out of nowhere. By the time something actually breaks, the warning signs have usually been visible for weeks or months. A few we see constantly:
1. Nobody remembers why a server is configured the way it is. Tribal knowledge that only lives in one person's head is a single point of failure, same as any piece of hardware.
2. Deploys require a specific person to be online. If a release can only happen when one particular engineer is available, that's not a process, it's a bottleneck.
3. Monitoring exists but nobody trusts the alerts. Alert fatigue from noisy, untuned monitoring is functionally the same as having no monitoring at all.
4. Backups have never actually been restored. A backup you haven't tested is a hypothesis, not a backup.
5. "We'll fix it properly later" has been said more than once about the same thing. That's usually a sign the underlying issue is bigger than it looks.
None of these require a full rebuild to fix — most come down to a focused review and a short list of prioritized changes.