I don't think I ever considered it until I was 30 books/volumes in to this novel I'm reading (not from this site, mind), but after so long, I've finally noticed something. The author seems to leave out details sometimes. Color, size, shape, and other descriptors are just missing. I chalked it up to lazy writing because of how much legitimate filler was stuffed in like repeated exposition. 

However, now I'm thinking it may actually be a technique. Providing the bare minimum description and leaving the rest up to the reader's bountiful imagination could let them fill in the blanks with their own preferred tastes. Such depictions can help prevent confusion or frustration from over saturated details. 

Maybe I'm just shooting in the dark here. What details do you guys leave out in your stories? Or if you're a reader, how much detail do you prefer in your novels?

i think it depends entirely on what kind of story i am reading. for example in a story with many characters and a lot of world building except for some very basic descriptions of the main characters. i feel like it would bog the sstory down too much if we stop and descripe every person we come across. in stories with more focus on the characters and their  interactions with each other more character description is appropiate. this is from a readers point of view.

when it comes to writing i think its easier with the first approach as well. descriptions for the sake of descriptions, just uses too much time you could be writing something more interesting. when a characters description plays a role in the narrative  though it is a completely different story.

Just like you said, it's often a technique. I prefer to let the reader imagine how people and stuff look beyond a couple of general descriptors. 

In my fiction, for example, the Sorceress is described this way: "She was tall, with very pale skin and dark hair, and wore a pitch-black dress with a pointy hat. But it wasn’t one of those oversized hats witches wear in cartoons; it was pretty small in comparison, and the whole attire was stylish as they come. Her lips were a deep red which saved her from throwing a goth vibe. And of course, there was something that couldn’t be seen, something beyond her physical appearance that made her imposing." And she is one of the characters that gets the heaviest description; the main character, Sarah, gets almost no descriptive details at all. 

In the last couple of chapters (that are up as of today; namely, chapters 19 and 20) you'll see objects described just enough to give a "steampunky" vibe, but in all cases most of the details are left to your imagination. 

Imagination is a powerful thing.

Setting plays a big factor for me.

If it's a scene where the character observes something new, for example, details should be worded out. On the other hand, if it's a fast-paced action scene, there should be as little description as possible because I find the number of words in a paragraph can determine the pacing. 

Something I go by is, what do you want your readers to feel when reading a certain scene? 
If you want to leave them wondering, use little and ambiguous details. If you want them to feel immersed, make sure to write about how the shadows danced under the moving lights, or how the rain trickled down the window panes. Something like that.

My fiction is in first person POV, so I usually imagine what kind of details the MC would pay attention to in that particular scene. I personally find that emotional scenes work best with immersive details at the start, then shift the details from the environment to the emotions the characters feel as the scene progressed into the climax.

As an author, I tried to be give enough descriptions to describe the setting and atmosphere the current scene is in.

Bobby stepped out of his home for the first time in 10 years. A cool breeze blew towards his tall, thin body and he was slightly pushed due to his weak condition. Nonetheless, he walked against the wind. The smell of grass and the warmth of the blinding, golden sun were intensifying. The wind became stronger, pushing the thin branches of those oak trees and bountiful of flowers some feet away. It was nothing but mother's nature all around his broken home. There were no other person, beast, or the small insect in the vicinity. It was only him and this empty world.

I don't believe I have big imagination, great creativity, or writing skills to provide the immersion to keep the readers lock on to the story. Sometimes, I question myself, is this good enough? Did I set the mood right? Was this enough to spark an imagery in the reader's head or get the reader's attention? Those are the fears I have when writing atmosphere, places, or people . That's why I give little details to describe a bit of the location and people, and let the reader's imagination to do the rest. I generally focused on characters, dialog, and a bit of action/movement.