I think this person is wondering whether to note, or not to note, at certain times. There are times we definitely would like to use the mental noting, there are other times when we generally know something is happening and do not have to continually note it. Here is a little example to help clarify this. We are sitting in the hall and everything is quiet. All of a sudden a bird flies close by and starts singing, and we get distracted. We note "hearing, hearing" and we come back to meditation. Now, suppose the bird keeps singing for twenty minutes. We're not going to note "hearing, hearing" for twenty minutes. We know that it's there, but we let it be in the background and we try to stay focused on our meditation subject. So our awareness of the meditation subject then may only be 80% of the time, and maybe the other 20% of our awareness is with the bird sound, but we're not actually distracted by it. We only have to make the mental note if we're actually distracted. If we can let things be in the background, then we don't have to use the mental noting.