This study examines how Big 4 audit partners’ career horizons influence their client portfolio management. Building on the premise that partners typically progress through three post-promotion career stages—the establishment stage (approximately ages 35–45), the maintenance stage (approximately ages 45–55), and the disengagement stage (approximately ages 55–60)—we posit that incentives vary systematically across stages and shape partners’ client portfolios. Our empirical results indicate that the number of clients increases as partners transition from the establishment to the maintenance stage. Conversely, partners reduce their roles as lead engagement auditors during the disengagement stage. In addition, partners approaching retirement are more likely to accept or retain clients associated with higher audit fees. Finally, we show that abnormal accruals, audit adjustments, and audit report lags decline monotonically across a partner’s three career stages. These findings support the argument that partners in later career stages leverage their experience and reputational capital to select higher-quality client portfolios.