I tend to do most of my paper reviewing during the weekend. No one is going to complain if I do it during my normal work hours, but the demands on my time are h

I tend to do most of my paper reviewing during the weekend. No one is going to complain if I do it during my normal work hours, but the demands on my time are high enough that it's hard to focus on it. So in some sense, for me, it is unpaid, outside of my paid day job.