An emergency can reveal which ordinary tasks were secretly holding everything together.

An emergency reveals which ordinary jobs were holding everything up. The moment the routine stops, you discover that some unremarkable task was load-bearing, and usually that one person was doing it without anyone noticing. Crisis is an unwelcome but very effective audit.

You can run a version of that audit in advance. Ask what would break if you were unavailable for two weeks, and whether anyone else could do it. The same question about the people around you is equally useful. Finding out which small tasks are structural is much better done in a quiet month than in a bad one.