If you ask someone what kind of writer they are, they might say they are an overwriter or an underwriter.
Both pertain to wordcounts.
Like the names imply, overwriters land well beyond their intended wordcount or what is the standard for their genre, whereas underwriters fall short of it.
But just as you'll find Plantsers between the Planners who go into a new project with a highly detailed outline and the Pantsers who prefer to dive in and figure things out as they see where the story takes them, I'd argue that there's a third zone in the middle of overwriters and underwriters.
Although your wordcount might classify you as one or the other, when you look at the specifics of that total and dissect it, you may find you're an overwriter in some areas and an underwriter in others.
Both can create issues within your WIP.
Lengthy passages of dialogue can become like talking heads, not grounded enough or hard to keep track of. Pages upon pages of worldbuilding might make the reader lose patience and beg you to get to the good part—i.e. the story. An overindulgence of historical details can read more like a textbook than an immersive work of fiction (as I and my past drafts can certainly tell you).
On the other hand, not having enough description makes it harder for the reader to orient themselves in the story. A lack of dialogue runs the risk of readers not being able to get to know your characters and, therefore, readers not being able to connect with them or want to invest their time in the book. Sparse historical details can result in a lack of context that an audience unfamiliar with your chosen time period would need to have a better understanding of the story (as I and my past drafts can certainly tell you).
My WIPs are pretty character-centric. I tend to go overboard with dialogue in early drafts and only have the bare minimum for narration and scene descriptions. This is likely because the characters are the first thing I know about any new WIP and have the strongest feeling of when I start writing.
When it comes time for the first round of edits, one of my priorities is striking a balance between abundant dialogue and scraps of description.
For clarification, I'm using "description" as an umbrella term here to cover scene descriptions and worldbuilding, dipping into character thoughts and backstories, character appearances and any related details, actions—essentially anything that isn't spoken by a character.
Ironic as it may be given how difficult I seem to find writing about what my story looks like, so to speak, I tend to take a visual approach to problem-solving. Plotting troubles, for example, I work through with sticky notes on a piece of poster board.
With edits, I've found "highlight drafts" to be immensely helpful.
I'm sure there is a more official name for them, but "highlight drafts" are a way to see the makeup of your book. It's a color-coding system where you assign colors to areas you feel you've got wordcount concerns about. For example, you might use blue for narration and yellow for dialogue.
If there is an overwhelming amount of yellow sections, that could indicate that there is too much dialogue in those spots and that it might be a good idea to break it up.
This is one of the few things I actually prefer to use a digital version of my WIP over a printout. I find it's just easier to highlight.
As an example, here is a page from Chapter Two of Bound to the Heart.
I've used teal for narration and magenta for dialogue.
This is a section I've edited fairly recently. It's arguably more polished than later sections I haven't gotten to yet, and the balance between narration and dialogue is about 50-50.
Now let's look at a section about 130 pages later in Chapter Fifteen.
No less than 90% of this page is magenta, and is therefore dialogue.
That's not great.
I haven't looked at this section of Bound to the Heart in at least a year (likely longer than that, honestly). And it shows.
This is reflective of how dialogue-heavy my writing had been before I really started to find my voice as a narrator. The teal bits scattered about this particular page are dialogue tags and action beats. They're choppy and frankly just kind of awkwardly there.
It's something of an eyesore. I'm cringing as I'm looking at it.
Highlighting it in this fashion makes it abundantly clear that when I do reach this portion in this round of edits, I'll want to pay attention to scaling back the dialogue and building up the narration, especially Eve's POV since this chapter is centered on her.
Not every page you write is going to be a 50-50 split between descriptions and dialogue. Worldbuilding or passages of emotional reflection might call for more narration as you explore your character's thoughts. Conversations with multiple speakers will likely have more dialogue. It just depends on what the story specifically requires at that time.
The main thing is keeping one element's presence from drowning out the other and overwhelming your readers.
I tend to keep the highlights to just picking out descriptions and dialogue, but you can break it down however you need. Maybe you pick out a color for each character to make sure they have an equal amount of time on the page. If you're working on foreshadowing a big twist, you could read through your WIP and highlight anything relating to it.
So many writing and editing techniques can be adapted for every individual writer's methods. Being a visual person, highlighting my WIP makes it easier to identify where my attention is most needed in edits. The disproportionate areas become obvious when they're bright magenta! Folks who do better with auditory exercises may run their writing through a text-to-speech program or read it aloud for the same reason (it's also a great way to catch typos and missed words).
It's really about finding the tricks that work best for you and your writing.