All rotations. My rotation literally told me unless I was sick/on my death bed, to not even try missing a day. I missed a day for IM because of food poisoning (vomiting ftw!) and was actually feeling sick at the end of the day prior to "calling in sick". The residents/attending were cool, but it's the administration that can be the problem. I emailed them that night and, to no surprise, they email me back requiring a written note from a doctor excusing me from clinic duty. Do you know how much fun it is driving to a clinic just to get checked for 15 minutes to "prove" yes you're sick? I got the note, but it's not fun. Also, I learned that the CVS/Walgreen's minute clinics don't do vomiting/diarrhea. Which I kinda get... but here I am driving 5 minutes and pulling over because I think I'm going to puke and then repeating that several times over.
So, ultimately, I'd say ONE day off is your best bet. You're expected to treat this like work, even if you're not doing any.