Our school has a policy against reusing the same essay for multiple courses, but why? The point of college is (or should be) to learn new things. If you have the chance to reuse an essay because the assignment is similar enough, then conjuring up an entirely new essay is hardly going to teach you that much more. If your old paper would get a passing grade in this new class, then you've already demonstrated that you have the neccesary skills. Insisting that you do it again seems to me that quantity is considered more important than quality. If it's an issue of getting the same credit for less work than your classmates, I'd argue that the workload is inherently unfair, with more talented students having to do only a fraction of the work that some others do for the same grade.