The necessity of reading out loud
One of the most satisfying phases of writing a novel is when you have a "complete" manuscript and you get to read through and find all the bits that are missing / need work / have to be re-structured. I relish having the words on the page already and then going back to discover where the holes are - so much easier than the blank page ... I love spending time creating spreadsheets mapping out each chapter and focusing in on the transition from one narrative to the next (particularly in my third novel where I've got multiple voices running into one another).
But when you get to a point where you've filled in all those holes, the next phase is the "complete" read-through. That is, reading out loud every single sentence to listen to its rhythm and trying to get a sense of how the whole sits together. I'm not a big fan of this time as it is often very fatiguing (it really can hurt the throat) and requires mental and physical energy. It is amazing, though, how hearing the work spoken can help to highlight where there are lags and where the voice no longer sounds like the character.
I'm always surprised when students admit to not having read their work out before submitting - there is that point in the workshop sometimes when they stumble over their words or pick up an obvious repetition - and I can always tell this is the first time they've spoken it out loud. I've heard them laugh at the idea of reading out loud to themselves, "but we read inside our heads", they argue. Yes, we do. But we learn how to read by speaking words first and the voice inside our heads is only the silent version of this. Making the words "live" off the page is, for me, an absolute necessity.