My kids ages 10 and older read the majority of their history and science work themselves, and are also always reading a literature book on their own. We have a read-aloud going during the day, and another dad reads at bedtime, and we don't require a narration on that last one. My ds9 reads some of his work on his own, but most is either read to him, read to me (by him) or we take turns reading together. He still needs work on focus and narration; other kids might be ready sooner to have their books turned over to be read alone.
So, for books I've not read myself, the boys read, and then come and hand me the book open to the section they've just read. I sort of skim as they narrate, seeing that they got the "main point" and were "getting" the reading. Now, I know with CM education there isn't a "right answer" or point they must get, but when we first began doing this, they were so far off at times that I knew that they weren't yet reading carefully and needed more work on slowing down, thinking about the text and making sure they understood what they'd read. Sometimes they might give a narration when we're out and about or I'm washing dishes or something, and in that case, I just listen.