Swapping one thing directly for another while trying to get the best deal one can out of the transaction is, ordinarily, how one deals with people one doesn’t care about and doesn’t expect to see again. What reason is there not to try to take advantage of such a person? If, on the other hand, one cares enough about someone—a neighbor, a friend—to wish to deal with her fairly and honestly, one will inevitably also care about her enough to take her individual needs, desires, and situation into account. Even if you do swap one thing for another, you are likely to frame the matter as a gift.
