I find a lot of writers fall into a trap: trying to write a story with the wrong ingredients.
No matter what story you want to write, you need the foundation of having the right amounts of the right things. The more of something there is, the less unique and distinct it is.
If there's loads of swords in your story, then a sword is not unique or distinct.
If there's only one sword, a lot of your story will be about why there's only one.
By carefully deciding how many swords to put your story, you get just the right amount of swordiness in your story.
Pretty basic, right?
One
One sword, and a lot of the story is about that one sword. Whether it's because that's the Sword of Light that no weapon can match, or whether it's because only one character in your office comedy show carries a sword.
While that one thing will always be distinct, you can make it more important by defining related things as blandly "not that". Or you can play it down by having a lot of variation.
For example, if your story is about twelve nearly-identical adventurers and a shlubby dude, the story is about the shlub. On the other hand, if your story is about thirteen people, only one of which works in a coffee shop... well, presumably, the others work in other places and the coffee shop employment will be distinct but not a major driving force.
This is also an easy one to accidentally trip over.
If your story features six white guys and a black lady... that one lady is going to stand out far more aggressively and distinctly, even if you didn't intend her to.
An example of this would be Bulk and Skull in Power Rangers. They're usually considered as "one unit", and they're really the only non-superpowered unit in the series. Because of this, they draw a lot of attention - people often feel more strongly about those two than about any individual rangers. As a plus, they can be split apart when needed and used as...
Two
If there's two swords, the story will be about how those two swords get along. A sword of fire and a sword of ice: who has them, how do they shape the world, what happens when they fight? You can see Lodoss Wars for an example of that.
Having exactly two of something draws attention to it. It can't be played down as much as if there's only one, or if there's a lot. Two is a really loud number.
Whether it's two swords that fight, or two amulets belonging to twin dragons, or two short people in a land of tall people, or two countries on the continent, or two species in your fantasy setting - it's all about how those two connect, and the differences in how they affect the world around them.
A lot of people write dualities like this into their stories without realizing how important it can become.
For example, you might set up a hero and a rival as being the only two people with a specific ability. If you then resolve their conflicts and have them move into the third act together, it's going to feel strangely flat and cheap... because their tension was far more powerful than whatever random baddie you're having them team up against. Makes more sense for the rival to take over as the big bad.
Some
If there's "some" swords, then the swords usually map to a specific category of character, and represent that character. They separate that kind of character from other kinds of characters, and become projections of that character's desires.
The easy example of that is Star Wars, where each space wizard has their own sword. It sets them apart from non space wizards, and the swords are usually considered to be extensions of the space wizard. If someone uses a sword that's not theirs, it won't work right unless they are "accepted", and if you find an abandoned sword, it probably still echoes with the space wizard that made it.
This may sound very spiritual, but it's an extremely handy way to extend your characters into your story space. Space wizards can have an outsized effect on the story because they are able to extend themselves into the story with their magic swords. The swords reflect and project who they are and what they want.
A non-swordy example might be superpowers in a comic book, or adventurer licenses in a fantasy manga. For less combat-centric things, it might be jobs in an office comedy.
When setting this up, it's important to choose a thing that extends the characters in a way your story needs. If space wizards had magic wands instead of swords, the story would feel more ephemeral and distant... but swords are immediate and primal, suiting the melodramatic conflicts of Star Wars. Similarly, in an office comedy, having distinct job roles extends the characters into the office space in a suitable way. If they had swords... well, it'd be funny, but it'd be a very strange office comedy.
"Some" may also be used to define a unified group, but in this case it's really just "one". For example, there are "some" ring wraiths, but in story terms there is "one" group of ring wraiths, and a lot of the story is spent on exactly how and why they exist. There are "some" Borg, but it's really just one group, etc, etc.
Lots
When there's lots of swords, they stop being unique and start being a functional prop. Their existence is important to the story, but individual swords are not terribly interesting and the things they do are often glossed over and taken for granted. They are often used as a framing device or narrative engine, rather than being used as swords.
For example, if absolutely everyone has swords, that says a lot about the kind of world they live in... but individual swordfights are likely to be glossed over and summarized. A Game of Thrones and The Hobbit show that.
If you want the swords to be more important, you have to come up with more important swords. So these are magical swords. Oh, too many magic swords? This one is a super-duper magic sword...
This isn't necessarily bad writing, but it's essentially separating the thing into "a lot" of ordinary swords and "some" special swords. This is why Bilbo's sword Sting can be easily thought of as an extension of Bilbo: short but sharp and shines when things get dangerous. There are "a lot" of ordinary swords and then "some" swords that are extensions of specific characters.
Again, swords are just an example. Another example might be monsters in Power Rangers, or species in Star Wars. They push the plot along and frame the story, but they are only distinct or unique as required to do that.
Summary
This is a very basic, easy, and primitive way to consider what ingredients you're adding to your story world.
Regardless of the type of story you want to write, if your ingredient proportions are wrong, you'll end up struggling to write what you wanted to write.
This is especially important when you're not writing the story.
If you're designing a world for a tabletop game, or for an extended series of stories, you need to arrange the ingredients to support the kinds of stories you want to exist!
At least, that's my take. Let me know what you think.
