Bankroll management is genuinely the foundation of sustainable betting. The basic principle is never betting more than you can afford to lose, and even more specifically, limiting each individual bet to a small percentage of your total bankroll. Most professionals recommend between one and five percent per bet, depending on your confidence level and experience. If you have one hundred units to start, you'd bet between one and five units per bet. This seems conservative but it allows you to survive inevitable losing streaks without going broke. Even the best bettors have stretches where they lose multiple bets in a row. Proper bankroll management is what keeps you in the game during those stretches.