> It's not the sunk cost fallacy even if the benefit of completion only justified the additional $1 cost; the $10 already spent is irrelevant, since if you choo

> It's not the sunk cost fallacy even if the benefit of completion only justified the additional $1 cost; the $10 already spent is irrelevant, since if you choose not to finish, you don't get it back, it's only the sunk cost fallacy if you are treating the cost already spent as a loss of not proceeding. Fair point, I should've said if the total benefit of completing the project is larger than the marginal cost ($1) of completing the project. > You sort of did the opposite fallacy, where instead of treating the sunk cost as a loss if you don't proceed, you counted it as a loss if you do. But the sunk cost is neither. Just to be clear, if the total benefit from completing the project is something like $0.50, choosing to spend the $1 to complete the project is an example of the sunk cost fallacy.