<p>Every place I have been a student or an adjunct, the policy is that you have to have a passing grade when you ask for the incomplete. There were no particular restrictions on the reason for the incomplete. </p>
<p>I, myself, had 2 in my college career. When I was a senior, one of my friends was killed in a car crash at Thanksgiving break, and I took an incomplete in one of the courses I was in (all that was left was the final) and I finished the course in January, without repeating it. In another (graduate) course, years later, I just did miserably, and took an incomplete at the very end, after which I had to completely repeat the course the following fall (ETA: with a different professor thank god). We had 1 year to get it done.</p>
<p>I have only had to give one student an incomplete, which his parents requested after he was hit with a tragic illness. I do not know if the student was ever able to complete the requirements, as the next step in their process did not involve me, but I don’t think it likely :(.</p>