I think Stephen Krashen's question about student goals is important to our cultural responsiveness in the classroom. Our students learn additional languages so they can mingle farther than they could before; define new identities for themselves. In each of their planned futures, what is the percent of perfection they will need to be understood, or to have a particular group's accent, considering the fact that studies have shown that listeners' ability to comprehend a second language speaker can vary considerably depending on their attitude toward that person's personality, ethnicity, or whatever; i.e., on listeners' willingness to comprehend. How much of our class time can we justify spending on perfecting pronunciation?
Sometimes you have a further instructional goal in mind. In teaching poetry in anglophone West Africa I go through all sorts of antics trying to get students who speak a regional syllabic-stressed variety of English to appreciate metrical patterns in poems written by native (phrase-stressed) English speakers.
Sometimes the student's goal is just to get a job. I recently was treated in Michigan by a South Asian physical therapist who had been learning in English since childhood, who told me about the four attempts he had to make to pass an oral English exam to obtain his credentials to work, particularly in light of all the non-native speaking doctors he has met in the US he considers very difficult to understand. He had a good point but I couldn't help thinking resentment might make him sometimes less willing than he could be to understand them.