A downswing shouldn't end your poker
Variance means even a clear winner will hit stretches of running 20, 30, sometimes 50 buy-ins below expectation. Bankroll management is the cushion that lets you ride those out without going broke: keep enough buy-ins that a bad run costs you a move down in stakes, not your seat at the table. The bigger the swings a format produces, the deeper that cushion has to be.