IMO it really depends. In my current role if I'm running any interviews I might talk to maybe 2-3 candidates at most. But in a previous role that could be more like 20-30, and when you're meeting that many people over a week or so and extracting a lot of information from each of them it is very hard to keep your facts straight without any notes.

I suppose as an alternative you could record the interviews, but then that sort of doubles the amount of work needed for each interview which is also a problem when you're doing a whole bunch of them.