The subjectline is not a verbatim piece of dialogue from back when I was a teacher. (Not that I could prove it even if it were.) It is not even a summary of what happened. The first quotation in the subjectline, however, is a paraphrased version of my students' skepticism of the lessons' usefulness, in one town in which I taught. The second quotation in the subjectline, in turn, is neither a quotation nor paraphrased, but the essence of my pre-emptive response, to students who never asked the former question, in another town in which I later taught. Whenever I needed to assign students a unit project that was neither a test nor a quiz, my go-to method for most units was to give them a presentation project, on a particular real-life use of the unit's concepts. I am not sure whether or not they'd have asked "when are we ever going to use this" without it, but I think it is worth making the students themselves answer, in front of each other, when they are going to use this, if only to make sure their motivation isn't impeded by the belief that useless knowledge is being imposed on them.