It depends on the situation and individual in a lot of cases. Accommodations seem to be most often needed in classroom or meeting situations where there are a lot of people who may potentially be speaking. They seem to be least needed in one on one interactions or small groups, which for some people, constitutes the majority of their day to day interactions. However, some CI users might still need an interpreter even for one on one contact, especially if they were signers before CI and their benefit from CI was limited to environmental sounds.
I never use an interpreter or notetaker in my current situation but I'm sure that if I went back into the educational environment where there was large class discussions I would need something too. However, if I was in an one on one or small group such as seeing the GP or going for a job interview with a small panel, I wouldn't need an interpreter.
Since a larger number of people from different backgrounds have CIs these days, there is going to be quite a lot of variability in terms of their needs.