Most bags I see have too much of the wrong gear; my rule is "Plan first; then pack."

Before you begin you BOB, GHB, or other bag, think about:

1. Whats your situation? Age, health, environment, resources
2. Where are you? Environment, season, geography
3. What is most likely? Zombie attacks are fun, but not likely
4. What is your goal? Stay safe? Get home? Re-start civilization?