Although previous research has shown that both trait and state conscientiousness are positively associated with a wide range of positive life and work outcomes, some studies indicate that acting in a conscientious way is effortful, and that behaving outside one’s conscientiousness related comfort zone (i.e., acting counterhabitual) may lead to cognitive or affective cost. Because these costs are not likely to be evident immediately, we examine how within-person fluctuations in conscientiousness relate to within-person fluctuations in emotional exhaustion, resource depletion, and negative affect, not only concurrently, but also in a delayed fashion and cumulated over time. In two experience sampling studies, we found that higher levels of conscientiousness are concurrently related to lower levels of emotional exhaustion, resource depletion, and negative affect. When looking at delayed effects, no conclusive evidence was found for affective or cognitive costs of (counterhabitual) conscientiousness. Finally, analyzing cumulative effects revealed that repeated negative deviations from one’s typical level of conscientiousness were positively associated to exhaustion, depletion, and negative affect, while repeated positive deviations were negatively associated with depletion and unrelated to exhaustion and negative affect. Altogether, our findings suggest that self-rated conscientious behavior is generally beneficial, even if this behavior goes against one’s typical behavior.