This is an interesting question and one that I can't answer for *your* manuscript because it would be kind of like me telling you, "You'd look great in a shag haircut" having never seen the shape of your face, having never known your personality.
So while I can't answer this question for your manuscript because again, I think each writer needs to look inside him/herself to find the best answers for their manuscripts, I can tell you how I came to discover my book needed sections and how that changed things.
And maybe through my process of revising and crafting my manuscript, you can ask yourself the same questions or perhaps, see what works best for your work.
For the longest time my manuscript had no sections. It was 56 pages of poem after poem after poem, all alphabetized. I wanted it this way because I wanted to showcase the A-Z order as well as have it almost appear like a dictionary, A poem leads to B poem leads to C...
I believe in about 2007 or 2008, I was either responding to a post by January O'Neil about manuscripts or thinking about it. She was either asking or discussing putting together a manuscript and somehow "sections" was brought up.
In responding to her (either in a comment or in my head, I can't remember which!) I remember making a statement that went something like this-- Sections are good because it allows your reader to have a break, its quite a challenge to keep the momentum of one's manuscript going for so long without them.
My manuscript, which had been a semi-finalist at the point, did not have sections. I looked at with new eyes. I reread my entire manuscript straight through and realized, that is exactly what was missing from manuscript--breathing spots!
My manuscript was a deep dive underwater, moving from emergency to emergency, but the reader never got to come up for air. It was tiring for me to read it in this new light. It felt heavy, it had an emotional arc, but there was no quiet space to absorb what I had written.
My book, which explores trying to find calmness in a chaotic world, never allowed the reader to find the calmness-- basically, the form of my manuscript was not in-sync with the content of the poems. While the speaker did and does, throughout the poems, my manuscript was kicking the readers butt by not letting her take a break, my manuscript had basically become the Sue Sylvester of the poetry world and did not want to give anyone a break!
So I looked at and asked myself: If this manuscript needs sections, where should they be?
It was very obvious to me after I asked that question. As I said in a previous post, my most vulnerable poems were "hidden" in the center. These are the letter poems of the book and the title poem (Letter from the Emily Dickinson Room) is in this section. I knew this poem needed to start off a section and so I added a break there so the reader could take a breath before we dove deep into troubled waters.
From what people have told me, that section felt like the emotional core of the book. While I believe there are a couple humorous poems in there, there are "heavier" poems as well. I read through until I came to a place where I felt the mood was changing and things were lightening up a bit, maybe even becoming a bit optimistic and added a section break there so I could breath again, so the reader could breath and there's a signal that the mood is changing, that we're moving to resolution.
Now on these section breaks, I could have used a symbol, a word, a number, anything to signal that we were at a place of rest, but I have had these quotes in my head that I have been wanting to use forever, so those became part of section breaks. Not only could I rest and relax here (and the reader as well), but the quotes act as a way to change the subject a bit.
The first quote: You write on your letter something which I sometimes feel also: Sometimes I do not know how I shall pull through. Vincent van Gogh
For me, this quote did two things--it signaled that there may be some letters poems approaching (there are) and it hits the core of this book "sometimes I do not know how I shall pull through..." This section break and quote allows everything to change speed, to say, "Wait, we might not make it. Let's slow down and see what happens..."
My second quote which begins the final section in the book: Let us go in; the fog is rising. Emily Dickinson -- were the last words of Emily D. I thought this was appropriate because I was beginning the last section and these words (even though her last) gave a sense of hope. It was an invitation to go into the last section and the fog--an image throughout my book since I basically live in a fogbank much of the year-- a literal fogbank though you could argue metaphorical too-- is rising. The depression, the anxiety, the sadness is lessening.
Once I added the section breaks I felt I gave my book some resting spots, benches on the path through the story. I guess that is how I look at section breaks for my own work, where do I need to take a breath? Where might someone else need to rest? In building this trail through my manuscript I tried to allow for scenes to happen all around as I was through (and later, as the reader walks through) and places to sit and absorb what's been seen.
So this is how I came to use section breaks in my book. Do I think all books need sections? No. Do I think your book could use sections? That is completely your decision. Will my next book have sections? I have no idea until I write that book.
I truly believe each manuscript is its own unique thing and there is no one way or best advice. In my ordering, I went against "putting your best poems first" mentality because for me, it didn't work. What I thought were some of my strongest poems were too emotionally heavy for the beginning of the book, if I placed them there without any context before it would have been like saying, "Hello, let me show you what I look like naked" before we even had a handshake. I couldn't do it.
So there you go, my thought On Section Breaks Worked for Me-- and maybe they'll work for you and maybe not. It's all your choice. And actually, more accurately, it's your manuscript's choice-- listen to what it wants, just as you listen to what a poem wants.