One Size Fits All

In many video games, clothing and armor can be worn by anyone, regardless of its source or the wearer's size or gender. These are usually Acceptable Breaks From Reality, as it's a pain to have exclusive sets of equipment for each character, but sometimes it just gets ridiculous.

Compare Informed Equipment. A default ability of the Adaptive Armor.

Action Adventure

 * Compared to other examples, it seems odd that this trope was averted in Gurumin: A Monstrous Adventure. There is a second playable character named Popon, who is, just like Parin, a little girl. However, attempting to put on any of Parin's headgear will result in the message "It doesn't fit" greeting the player.

MMORPGs

 * World of Warcraft provides an extreme example: It's possible for a Tauren (an 8-foot-tall bipedal quasi-bovine) to wear gear looted from a leper gnome.
 * Also, that the same piece of gear, when worn by a female, instantly becomes not just smaller, but also more revealing/form fitting.
 * Exactly the same in Final Fantasy XI, but replace Tauren with Galka, and Gnomes with Tarutaru.
 * Not only that, when worn by draenei or tauren, pants and robes magically sport tailholes.
 * And shoes lose the shoe part, and become something like legwarmers. Note that you can later give the shoes to someone without hooves and have the shoe part reappear.
 * Also, any robes, pants or shoes that a Forsaken puts on will immediately have large holes ripped in the elbows, knees, and toes, all the better to show off their decaying skin and exposed bone.
 * The MMORPG Guild Wars is a notable exception, as all armor of any type (including gloves and shoes) must be custom-built by a merchant NPC and is only usable by the character that bought it, although it can be salvaged for crafting components or upgrades (always less than what went in). Weapons are sharable unless you want them customized, in which case they get a slight damage increase but can never be sold again either.
 * Averted in Retro Mud, where every equipment has a numbered size, as does your character. This makes it really annoying to find equipment if you're not playing as a humanoid.
 * Partially averted by Runescape: Early on in the game's history, a blacksmith NPC existed solely to convert men's armor to women's armor and vice versa. This was eventually done away with in a major game upgrade, and the blacksmith's shop was replaced with a burnt, abandoned shell. However, both plate legs and plate skirts exist as armor pieces and unwearable armors from other races, such as goblins, exist.
 * Unwearable until you turn into a goblin, that is.
 * Both averted and played true in the MMORPG Star Wars Galaxies. The same shirt or suit of armor can fit a 6-foot human and a 4-foot Bothan; however, Wookiees and Ithorians can only wear specialized clothing and armor, certain types of clothing (for humanoids) are gender-specific, and certain species cannot wear certain forms of headwear or helmets (partially due to the graphics issues).
 * Averted in Puzzle Pirates. All females are exactly same size, so one size truly does fit all females. Ditto with males. However, cross-dressing is never allowed, leading to oddities such as bandannas that can never be worn by males.

Roguelike

 * This has been cited as a justification for the fact that you can only wear one ring on each hand in roguelikes: rings come in only one size, so they just barely fit onto a orc's pinky, and are dangerously loose on a hobbit's thumb. All this goes out the window to a certain extent in Nethack, since rings and amulets (but not body armor) can be worn not just by humanoids, but by jellies, snakes, and intelligent clouds of vapor.
 * The ability to wear rings as a fingerless creature is limited to rings that were on your finger before you changed shape and is there to avoid making it too easy to get rid of cursed rings. If you turn into a fingerless creature, you can't put on new rings and the old ones that were there before you changed shape are stuck and won't come off. In effect, they change with you.
 * The real reason, of course, probably stems from the D&D tradition of only allowing players to wear two magical rings at once, citing interference between their enchantments.
 * The game of Dwarf Fortress abstracts this issue into size categories, so that clothing and armor is only usable by races of the same size category as the one that produced the item. Previously, there were also 'stout' and 'narrow' categories.
 * Averted for some items in the Roguelike Incursion: many weapons which can be wielded one-handed by normal sized beings must be wielded two-handed by small beings, and small beings can't wear normal sized backpacks.
 * A common complaint in Angband was that a gnome could wield a weapon that was heavier than him with strength-boosting equipment.

Real Time Strategy

 * In the original Ogre Battle, any unit can equip any armor. Even armless creatures like dragons can wear mail or use weapons without problems.

Role Playing Game

 * In Super Mario RPG: Legend of the Seven Stars you can buy Work Pants that will fit any character, even though Bowser clearly wears no pants.
 * Many Final Fantasy games will have armor or clothes that can be passed around relatively universally, even if the sizes of your teammembers range from "7-foot-tall muscle-bound dude" to "8-year-old girl."
 * Especially odd in Final Fantasy IX, when many people on your team aren't even the same species, with all the differences in physical build that would imply. However, they at least make an attempt to address this trope with some male/female specific equipment.
 * Partly averted in VI, which has armor only females can wear. However, considering they mean Terra, Celes, or Relm...
 * This trope is fully in evidence in the Champions of Norrath series. In Return To Arms, for example, a piece of clothing will change from a form-fitting, cleavage revealing blouse on a female human mage to a pair of shoulder pads that appears to be made of leather and bone on a male lizard man.
 * In Dragon Quest V, you and your friend Bianca can wear the same armor as adults that you wore at age 6 & 8. Later, your own kids can wear the same armor adults can.
 * Similarly in Might and Magic VI and on, where the same suit of leather, plate or chain is equally form-fitting and functional as it is passed from dwarf to elf to goblin to human to half-orc and from male to female and right back again.
 * Averted in The Elder Scrolls 3: Morrowind - the "beast races" (reptilian Argonians and catlike Khajit) could not wear boots due to the unusual shape of their feet. Played straight in the other games in the series. This can be justified in the case of the Khajit, who supposedly range from feral jaguar-men to Cat Girls, but there is no explanation for Argonians.
 * Particularly jarring in Oblivion is that if you play as a female character and steal clothing or armour from a male character (or vice versa), the item actually magically changes appearance when worn - trousers become skirts and shirts become blouses.
 * An extreme example from Oblivion is the "Huntsman's Vest", which, on male characters, is a simple fur vest. On female characters, it becomes a fur bra.
 * It's a little better in Fallout 3; however, you can blast your enemies limbs and head off and still take the armor, which magically becomes whole again. Vault-issued sewing kit, perhaps?
 * Some clothes even had different appearances depending on the wearer's gender. If your character is male, you can kill a woman in a dress, take the "pre-war casual wear" and put it on as pants and a shirt. And vice versa.
 * Earlier Fallout titles generally did not allow players to loot armour from corpses, but armour and clothing will fit any character just fine. The massive Sulik and the tiny Myron can both wear the same Leather Jacket with no problems.
 * Averted in Planescape Torment - everyone who winds up in your party has their own armour or clothing, and refuses to take it off. You can buy armour for the party Action Girl, but you can't wear that (or the clothing it replaces).
 * This goes even further - one character cannot wear earrings due to the shape of his ears. Another, being a skull, is unable to equip anything except a set of teeth. This does not explain his large inventory.
 * The game lampshades Morte's large inventory space despite being a skull by telling you that you shouldn't bother thinking about it.
 * Averted in Mass Effect. All species use different types of armour, save for the asari, who are close enough to human (female) shape that they can wear human armour without hitch. On the other hand, all species use same type of weapons, even though it's a bit hard to see how the massive krogan even fit their fingers on human-sized triggers.
 * And still played straight, as human armour fits all sizes of humans and asari and has a form-fitting breast plate only when worn by a woman.
 * Averted in Arcanum where torso clothing comes in three sizes: small, medium and large, and Ogres can't use pistols and other small firearms due to their large hands. Of course everything else is one size fits all.
 * Averted in Secret of Mana, where the female character can wear certain items of clothing not available to the male characters; in Seiken Densetsu 3, each character is required to buy a unique set of armor (and weapons).
 * But still played straight as the Boy and the Sprite can wear (most) of the same armor, even though the sprite is about half the size of the human male.
 * In The World Ends With You, clothing plays a major part in the gameplay. As long as you have a high enough Bravery level, any character can wear any outfit. This includes the male lead Neku wearing gothic lolita dresses.
 * Or for a real brain-breaker, Beat.
 * That's not so bad-- they're Invisible to Normals, plus Gameplay and Story Segregation doesn't let you actually see the outfits (thank God)-- but this editor still hasn't figured out how you wear a potted plant.
 * As a codpiece.
 * You could wear it as a hat, but it wouldn't stay on very well unless either you turned it upside down and just wore the pot or strapped it to your head.
 * In Sonic Chronicles The Dark Brotherhood, all the footwear that Cream and Amy can wear, Big can wear. Boots that can be worn by Rouge can also be worn by Eggman. Gloves can be worn by any non-robot.
 * The Rouge/Eggman example may be justified by the extremely disproportionate size of furry hands and feet. While the human characters' limbs are also disproportionate, they are less so, meaning a 6'2", 282 pound human could hypothetically have the same shoe size as a 3'5", roughly 90 pound bat.
 * Messed about with in the first Star Ocean game - most characters are roughly the same size, but Ilia (a kung-fu-fighting woman and Pericci both have unique sets of clothing that only fit them. On the other hand, Phia (a female warrior) wears the exact same stuff as Roddick and Cyuss (male ones). Oh, and some characters have tails, but since the game takes place on a world where almost everyone has tails, the assumption is that the tail holes are always there but the human characters just ignore them.
 * Muppy, a slug-like alien from Mana Khemia Alchemists of Al Revis roughly around a fourth of the size of the other playable characters, can still equip armor that comfortably fits his otherwise human allies.
 * In Dragon Age: Origins, anyone can wear any suit of armor. For example, male dwarf's heavy chain mail will fit the female human. And vice-versa.
 * Averted in Venetica: any armor found by the player has to be taken to the blacksmith to be tailored.
 * In Dubloon, you can even have your Team Pet Ricky wear armour if you wish so.

Simulation Game

 * Played straight in Animal Crossing series because having Your Reward not fit your Virtual Paper Doll wouldn't work so well with the sharing and communication aspects of the game.

Turn Based Strategy

 * In the Disgaea series, the only equipment restriction is that monsters have to wield monster weapons, and humanoids have to stick to the six other weapon types. Otherwise, any unit can wear any piece of armor (Even the dresses and bikinis) or weapon regardless of gender or species, and can even wear three pieces of the same armor type, like three pairs of shoes, or three pairs of glasses. The weapons used by humanoids are the only visible piece of equipment.
 * In Shining Force II, rings, bracelets and similar generic accessories can be worn by characters who don't have hands.
 * In the handheld and NES Fire Emblem games any equipped weapons will magically adjust to the style that the character wielding them likes. A Hero using an Iron Sword will wield a massive broadsword. Pass that same sword to a Myrmidon and it's a katana. Finally give it to an assassin and it's a pair of daggers.
 * Some of the SNES entries, and Path of Radiance/Radiant Dawn, have weapon appearance based on the weapon instead of the person holding it, however.
 * In Heroes of Might and Magic, any hero can wear or wield any artifact, breastplate, sword, shield, boots, etc. regardless of the fact that some heroes shouldn't technically be able to (genies for instance shouldn't have feet).

Wide Open Sandbox

 * Averted slightly in Grand Theft Auto: Vice City. In order to do some insanity, Tommy and his sidekick Lance ambush two cops in a garage. They tie them up and steal their uniforms. Tommy declares that his are 'a bit tight in the crotch'. Lance then claims the same. Oh, Lance.

Anime and Manga

 * Saiyan battle armor from Dragonball Z has this effect: the suits come in one size, but are extremely elastic, and can expand to fit any wearer comfortably... even when that wearer is a 50-foot tall giant ape!

Comic Books

 * What about 5'8", 145 lbs Tim Drake wearing a Batsuit fitted for the 6'2", 210 lbs Bruce Wayne in Battle for the Cowl?
 * Interestingly, in Knightfall, when Tim gives Jean-Paul a Batsuit, Tim mentions that it's one fitted for him and that the original one worn by Bruce is on injured reserved.

Film

 * Partially averted in Ever After: Danielle repeatedly steals Marguerite's dresses to disguise herself as a courtier, and while the improbable fact that her stepsister's clothes fit her perfectly is never mentioned, Danielle does comment that "the shoes are too big," and she ends up wearing her ordinary servants' shoes to court.
 * In Species Sil steals clothes from a female train conductor to blend in, yet somehow the overweight, middle-aged woman's clothes fit perfectly on Natasha Henstridge's model body.
 * In Stage Beauty, Maria steals Ned Kynaston's dress to wear to dinner at the palace. Kynaston, being a man, has broad shoulders and a large torso, and Maria is much smaller than he is, yet the dress fits like it was made for her.
 * Pointed out in the Mystery Science Theater 3000 version of Space Mutiny. Hero David Ryder beats up an Enforcer, strips him naked and takes his uniform. As Tom Servo says, "So, he fits into a uniform that was really restrictive on a tiny guy."

Literature

 * In a possible model for this trope, the titular Rings of Power from The Lord of the Rings are capable of altering their size fit their present owner (and to treacherously slip off their finger).
 * In the movie, when Isildur picks up the ring after destroying Sauron, it actually shrinks in his hand.

Live-Action TV

 * In Buffy the Vampire Slayer flashback Spike steals his leather coat from a dead Slayer, who naturally is much smaller than him, and who wears quite form-fitting clothing. The coat visibly grows between scenes when he pulls it off her.
 * In Quantum Leap, it's established (usually) that Sam Beckett is leaping around in time in his own body, and he merely takes on the appearance or "physical aura" of the person he's leaped into. Despite this, his hosts' clothes always fit him perfectly, even when he leaps into people much smaller than he is. In one of the comics, Al mentions that the project programmer, Gooshie, has considered the problem and theorized that the leap causes a disturbance in the molecular structure of the clothes, making them unstable. Sam considers this theory for a moment and concludes, "Gooshie reads too many comic books."

Tabletop Games

 * The tabletop Dungeons and Dragons both uses and avoids this. Armor and clothing are treated realistically, as individual pieces can't be worn by someone the wrong size and/or shape (a halfling can't wear chain mail designed for an orc). However, many magical items are explicitly stated as resizing themselves based on the user, so a giant can wear a normally human-sized magical ring, and a tiefling with goat hooves could wear a pair of magical boots.
 * Plate mail also only fits the character it was made for and has to be "fitted" to be worn by someone else.
 * This is actually unrealistic; with adjustable straps it's possible to make a plate armour that will a fairly wide variety of people, as long as they aren't very far off from the average size in height or weight. It won't fit as perfectly as armour made by your measures, but grand majority of the Medieval soldiers and knights had no trouble using such equipment.
 * Every larper or reenactment participant that has worn plate mail can attest to that, as the armors worn are just a little lighter than the real thing, and usually one tries a friend armor before buying ones own.
 * This also varies heavily by edition, with some saying to not worry about it, some requiring a massive fee almost the cost of creating a new set, and some allowing anything to change size as long as it's magic.
 * This can get beyond ridiculous at times, when the rules suggest specific magical items created for colossal dragons (like tail-guards and horn-covers) which will change shape entirely to fit the analogous part of a humanoid.
 * However, many video games based on D&D dispense with these rules,meaning you can freely swap that plate mail suit between a seven foot tall half-orc and a three foot halfling.
 * This makes sense though, since the designers want you allow players to roll up characters of different race/gender combos, it would take a lot more programming to whip up random items with a decent chance of actually being used rather than sold.
 * Earlier editions--up to 2d edition AD&D--were heavy aversions. One supplement had a chart for a percentage chance of swapping armour between species, and an additional modifier when gender comes into play. And reminded the DM that Rule Zero still applied, so they should definitely remind the 6' barbarian heroic human built like a square of muscle that he's not going to have any chance at all putting on the magic chainmail from the dead female elf.
 * Averted in GURPS armor for characters larger that a normal human is heavier and more expensive. Some ultra-tech armor will resize itself within limits.
 * Averted in Shadowrun when armour for dwarves is actually more expensive than armour for humans, because 90% of the population are human so dwarves often need to order specially and end up paying as much as trolls. The same is true of vehicles, guns, you name it. (Well, guns are less of an issue for dwarves, but trolls still need them customised)
 * The boardgame Talisman has armour that will fit anyone from a sprite or a dwarf up to a minotaur, a troll, or even a centaur. The minotaur cannot wear a helmet; a few other characters are debarred from armour use for arcane reasons, but none because it simply does not fit. What's more, if the troll picks up armour that the sprite was wearing it fits just fine and is fully effective with no adjustment whatever.

Web Comics

 * Averted and lampshaded in this Awkward Zombie comic.
 * Goblins generally averts this trope; size modifiers have been discussed in relation to large weapons, and the goblins sometimes reject human-sized gear if it's unusable to them. The Axe of Prissan and the suit of armor associated with it notably play this trope straight, justified by the fact that they're magical and designed to reshape themselves to suit the needs of whoever uses them.
 * Similarly to the above, this is averted and lampshaded in Castlevania RPG, and in addition Link spells out why this trope doesn't plausibly work.
 * In Gunnerkrigg Court Annie made boots as a gift, so she had to compensate for lack of bootmaking experience and lack of measures with excess of magical skill. It works.
 * There are special suits of clothing in El Goonish Shive that fit this. It is justified in that they were designed to be worn by shapeshifters, which can change body size considerably.

Web Original

 * Cracked Photoplasty advertises one-size-fits-all armor in Ads for Products That Must Exist in Video Games.