- It saves server resources. Areas that are instanced don't need to exist until they are needed. Uninstanced areas are up and running all the time.
- It helps preserve the sense of significance of the player's actions.
- It alleviates player congestion. Uninstanced areas can have more players trying to use the area than it can support, leading to long waits; instanced areas can support player activity up to the limits of the server, which is higher than the mere limits of the area.
- Alleviating congestion also helps prevent strife between players, as some players will try and jump in ahead of the players who have been patiently waiting.
- Alleviating congestion allows an MMORPG to include more solo and small group content, broadening its appeal.
One downside to instancing is that excessive or otherwise inappropriate use of instancing can lead to a world that feels "empty and barren" of other players.
Pseudo-instances are where a certain number of copies (usually three) of the "instanced" area are part of the area and are up and running at all times. The pseudo-instances are widely separated from each other and the "lobby" area. Players are teleported to an available pseudo-instance when they enter the "instance" and teleported back to the lobby upon completion. If all pseudo-instances are already in use, everybody else will have to wait for one to become vacant.
Because the pseudo-instances are separated from each other by mere intra-area space rather than by zone borders, and because the server blindly trusts whatever position the player's client reports for that player, it is possible to use certain banned third party tools to warp into a pseudo-instance already in use by other players. Other third party tools can be used to increase the draw distance to the point where the individual pseudo-instances can be seen from the lobby, floating in empty space.
The game did eventually receive an actual instance system, known to the development team as the layer system. It is used by some Treasures of Aht Urhgan and Wings of the Goddess content. It is prone to crashing, overcrowding, and bugs, including the notorious salvage duplication bug. Content known to use the layer system includes:
- Wings of the Goddess storyline missions
- Certain Campaign Ops
- Moblin Maze Mongers
- The Notorious Monster battles that occur when Sandworm sucks in players using Doomvoid
There is extensive use of the instancing system through the means of player-initiated "duties". Duties represent the number of available instances the server can create, as well as referring to the actual content contained within them. The term interchangeably refers to both.
Many examples exist of the "duty system" and it has many applications in the game's advancement of both main story content and side content. It serves as the backbone of the game's core play loop, and allows players to work together or alone at their own speed and convenience.
The "solo duty" is a specialized trail of specific enemy combinations and mechanics used to either illustrate specific skill use and role expectations (as is the case with class and job advancement quest lines) or to separate the player from the general game population and make their efforts more meaningful.
The "dungeon duty" is a gathering of four players within specific job roles working in unison to gather equipment or defeat a specific story-line foe. Later updates have added the ability for these normally cooperative efforts to be undertaken alone, with non-standard roles, or while using equipment far advanced above its intended design. They are known in-game as either an "unsynced duty" or "fixed party instance". Version 4.0 extended the unsynced duty to include all instanced content in the Final Fantasy XIV: Heavensward expansion.
The "raid duty" or "trial duty" are instanced areas designed for eight players to either defeat a single strong foe in a small arena (known as Trials) or tackle a series of highly difficult challenge battles and puzzles (known as Raids). These serve double duty as optional end-game content and main story advancement content, with trials making up the bulk of the latter and raids making up the bulk of the former. Depending on the current update and maximum item level (as well as the character attributes meta-game), players may be more focused on the Extreme difficulty Trails or the Savage difficulty Raids to serve as the ultimate test of their skill and accrued equipment.
The "alliance raid duty" dungeons support up to 24 players who work in unison, and are often connected by a single storyline thread (such as "The Crystal Tower" representing the Final Fantasy III final dungeons). After their initial release, they are known to contain the highest level equipment for their update and can only be entered on a weekly basis to prevent the content from being exhausted too quickly. They also drop or are used to acquire the necessary items to buy or upgrade the other existing content's equipment to be roughly equivalent to the kind dropped within.
Other notable duties exist which don't necessarily follow the standards of the above.
Duty Roulettes will pick a random instanced content and match players with parties attempting them based on their filtering criteria and the specifics of the roulette itself. For example, the "Main Scenario" Roulette will pick either Castrum Meriadnum or Praetorium to allows players who have passed this content to assist newer players in exchange for gil, experience (when possible), and Allagan Tomestones. This feature was added during A Realm Reborn's 2.3 update.
The Palace of the Dead is a Deep Dungeon composed of many smaller instances that restricts the player's equipment and levels to those only usable within the instance. It has a fixed level maximum of 60 and 200 floors (20 instanced areas). To keep data concurrent across all instances, the player must create individual "save files". Their unique weapon and armor are tied to their actual character data and exist regardless of class or job, and they can be reset by forging them into a real weapon or armor piece usable in the core game at certain ranked levels.
The Diadem is an instance taking place in Heavensward's Sea of Clouds region. It allows players to either level a Disciple of the Land class or a combat class as they explore an ever expanding and changing region by airship. It was removed temporarily due to lack of interest and poor design, but has been added back as of update 3.55b.