Projection bias in effort choices

I model individuals working on a long-term task who, due to projection bias, underestimate changes in marginal disutility. At the start of each day, when current disutility is low, such overestimate how much they will work, and as grow tired from working, plan work less less. Despite these fluctuating plans, face decreasing returns effort, optimally, yet if commit advance, overcommit. When facing increasing returns, may repeatedly quit, rested only give up tired. In all-or-nothing tasks, starting-and-quitting can lead wasted effort never-to-be-completed or completing them by inefficiently little early on.