It takes me about an hour to draft a case report. I expect that a student with a good grapple on what happened in the case (ie they were there and we discussed it) to take 4-5 hours to make a basic draft. Universally, (have now done 6 case reports with students), I have re-written the entire case report while sitting next to the student, explaining why I am changing what they wrote to my writing. It typically takes me about an hour to do that, ie the same amount of time as if I wrote it myself. But, instead of remember/figuring out the chronology of the case, I am spending the non-writing time explaining to the student how to communicate their ideas a little more fluidly. It is normal for very few words to be used from the student's draft. I then have the student send the draft to the surgeon/PI and we get feedback, make the edits and send it out to the journal. It is rare for any single person to invest more than 10 hours on it. Now, if the student has to do outside research because they have to figure the case out (ie they weren't present) or because they have no idea what is going on (ie they know nothing about the field that the case was in), that adds to the total time, but even then, I have a hard time imagining that taking more than 10 additional hours. If it is taking longer, they are getting poor direction or are doing something wrong.