Consider the little mouse, how sagacious an animal it is which never entrusts its life to one hole only.

Depending on a single arrangement is the risk most people underestimate. One employer, one client, one route home, one person who understands how the system works: it functions perfectly until the day it does not, and then everything fails at once. Prudence is mostly having a second option before you need it.

Look for the place where you have only one of something important. Build a modest alternative while things are calm, since that is the only time it is cheap to do. It does not have to be as good as the first one, only real.