They may face different fates, depending on multiple factors.
Racked states,
The answers aren’t as exciting as people want them to be, mainly
because television shows and movies are businesses. They have
accounting departments and detailed asset tracking. Costume
departments don’t really have any say on what happens to the clothes;
it’s ultimately up to the producers and the studio (HBO, Sony, etc.).
Fashonista states that
The number one rule of thumb that audiences might not realize is that
the costumes are officially property of the studio producing the show.
If the costumes were made for the show, and being owners of them, studio may choose one or more options for the lot at once or choose separately. again, decision depends on multiple factors.
Or sometimes they rent costumes from third party, like costume shops.
So back on what will happen to 'em,
1. They gets thrown away
They were kept in studio warehouses or some other storage facilities
From Racked,
The thing most people don’t realize is that everything that is bought
in every department is recorded. Shows are typically set up as limited
liability companies that are specific to that show only. They often
have a parent company, such as HBO, Sony, or ABC, but each show
operates within its own budget, and so each show is responsible for
each individual piece of clothing. Accounting departments keep track
and mark things above a certain value (usually $100) as an asset,
which means they need to know where it is at the end of a shoot.
These departments usually implement their own tagging systems so that
during wrap it’s easier to find all the assets (accounting generates a
list which needs to be checked off, with the location of every piece
notated).
“An extraordinary amount of time is spent tracking down and ID’ing
things,” Liz Shelton, another experienced ACD in New York, tells me.
“Unless you’re doing an incredibly low-budget job where they cannot
afford storage, most studios want everything featured back and
sometimes have auditors on the case. I try to get production to donate
the unestablished (pieces not seen on camera) and non-asset items to
places where the clothing can go to people in need. Sometimes that
works and sometimes not.”
2. They were kept and used for re-use (for same show or different show).
From Racked,
Most studios have the policy that no asset can be sold, promised, or
given by anyone but the executive producers. Everything is held until
all edits are complete and the time for reshoots is past. Some of the
big studios, like Disney and Warner Brothers, have their own rental
house businesses, so everything gets filtered into those. Studios will
also occasionally roll over stock from one show to another. When HBO’s
Vinyl wasn’t renewed for another season, a lot of the clothes went to
The Deuce. Television shows rarely get rid off anything until the show
is cancelled. Everything is catalogued and recorded from season to
season. Principal actor clothing is kept in their permanent “closets.”
Even if an item is never worn again on the show, it stays, because you
never know when a random flashback scene might appear in a script.
3. Sometimes, recognizably iconic costumes go into archives.
From Racked,
Studios or producers hold onto the costumes that might be a big deal
later on. Most of the larger studios have pretty extensive archives
and storage. Robert Rodriguez, for one, keeps a huge amount of stuff
from his films in storage in Texas.
4. Sometimes studio gave the costume to actor/actress.
From Racked,
Still, producer Michael Flannigan tells me that sometimes, costumes
are gifted to cast members. “Several actors have it in their contracts
that they get the pick of their wardrobe,” he says. “Other than that,
we have a fire sale, typically only for the crew, at the end to sell
as much as we can, same as we do with props and set dressing.”
(There was one icident Deadpool star Ryan Reynolds steals his costume and goto public without studio's any knowledge, which was intended as some kind of marketing stunt )
5. Sometimes they were sold to the public
From Racked,
If actors are patient enough to wait until a show wraps, they could
also take advantage of costume and prop sales that are open to the
public — meaning to other productions, costume houses and even to you
and me. "Girls" and "Orange is the New Black" costume designer Jenn
Rogien worked as an associate costume designer on the 2009 series
"Kings," which was canceled by NBC after one season. She recalled one
specialty-size actor who ended up purchasing a bunch of his own
character's suits. "He had a really hard time finding suits,"she said.
"So he was thrilled to be able to buy several already tailored suits
for his [regular] life and to wear to auditions." Rogien also scored
big. "I ended up buying a character’s shoe closet because she had
really fabulous shoes," she laughed.
Note: I'm on a plane and this answer may not properly formatted, organized or good as I'm thinking it is.
You can read my sources below and it may provide much better insight. I'll put some more resources if I could find any.
Racked
Fashionista
Quora1 Quora2 Quora3
Mid-day
ScoopWhoop
East Bay Times
iDiva
Dailyhunt
HowStuffWorks
SmuggBugg
Yahoo Answers
Radiotimes
Update : Storing is only a one option and it isn't used for all the items. As I've said in the begining, it depends. Only if they got reason to store, then they go for the store/keep option. In storing option, they have multiple options too. Storing in production company/Studio (Sony, Warner, Disney etc..) who may have bigger warehouses, or store in third party storage units etc...