Bankroll management is the practice of controlling how much you bet relative to your total gambling funds. The goal is to maximize playing time and minimize the risk of going broke. A common rule is never risking more than 1-5% of your total bankroll on a single bet or session.

For recreational blackjack at a $25 table with basic strategy (0.5% house edge), a bankroll of $1,500-$2,500 gives you enough to handle normal variance over a 4-hour session. Professional card counters typically need 200-500 times their minimum bet as a total bankroll.

Risk of ruin is the probability of losing your entire bankroll. Even with good bankroll management, there's always some risk. The risk decreases as your bankroll size increases relative to your bet size. At 1% per bet, your risk of ruin in a negative-EV game is much lower than at 10% per bet.

Expected session length depends on three factors: your bankroll, your average bet size, and the house edge. The formula is: Expected Bets = Bankroll / (Bet Size × House Edge). For a $500 bankroll at $10 bets on European roulette (2.7%): 500 / (10 × 0.027) ≈ 1,852 bets before expected ruin.