How important is bankroll management for low-stakes players?

I think bankroll management is one of those subjects that isn't very exciting, but it probably makes a huge difference over the long run. Even a good player can have losing stretches. What bankroll rules do you personally follow when playing low-stakes tournaments or cash games?

Bankroll management is about survival. Use 100 buy-ins for tournaments and 40 for cash games. If you suffer significant losses, drop down in stakes—without letting your ego get in the way—to protect your bankroll from variance.