Session length directly affects decision quality because cognitive fatigue deteriorates the complex decision-making poker demands. Cognitive psychology research indicates that high-quality decisions are more difficult to sustain after 4-6 hours of intense focus. Professional players frequently limit live sessions to 8-12 hours with regular breaks, and online grinding sessions to 4-6 hours of high-quality play. Factors such as hydration level, nutrition, prior sleep quality, and stakes involved all affect optimal session length. Ending sessions while still playing well is more valuable than attempting to recover losses with fatigue-deteriorated play.