There is a question, How to promote code reuse and documentation?, which I think is well worded, but new and only got a few average answers so far. It was also suggested that it's a duplicate of How Visual Studio could help to avoid duplicating code?, but the later is low voted and the wording is more specific and not really similar. But that question has a very good generic answer that would be perfectly applicable to the first question.
Should it be closed as duplicate? They don't look like ones. Or should they be merged? Or is there some other way to make the answer visible on this question?