Diminishing returns (DR) refers to the mechanics used to prevent bots and exploits from disrupting the economy and gaining an unfair advantage over legitimate players. There are several types of DR in the game, each of which is character-based with the exception of dungeon DR, which applies to the entire account. Although DR could affect most activities that have potential for abuse, very few players will experience it during normal play.
DR is needed for dungeons due to their ability to be repeated quickly. Similarly, it is applied to Dynamic Events to limit players from exhaustively farming one area, reduce congestion in one particular map, and to discourage illegal activities such as botting.
- Dungeons, in which the completion rewards for an account are cut severely after the first run for each path.
- Open world:
ArenaNet has never shared the precise details of how diminishing returns is implemented in Guild Wars 2, with the exception of dungeon reward DR. From various posts by the company's staff, players have pieced together the general concepts:
- The more often a character loots from similar foes within an area, the more quickly DR triggers.
- Once triggered, the impact of DR will increase until you won't get any loot at all anymore.
- The only way to "remove" DR is to go somewhere else for a length of time that is partly random and partly dependent on how much DR that character has. Usually, it lasts no more than 15-20 minutes if the character actively participates in other content.
- Except for dungeons, DR is character based, which means:
- Swapping characters results in a fresh start, with no DR.
- Each individual character must leave the affected area for a time in order to reset the DR, i.e. swapping to a second character does not help reset DR on the first.
[verification requested] Dungeon DR reduces the completion rewards for completing the same path more than once. It affects the direct rewards for completing each path and applies to dungeon tokens, experience, karma, and Empyreal Fragments. Unlike other forms of DR, dungeon DR is account-based, meaning it cannot be avoided by running the same path on multiple characters. It works in two ways:
- The bonus reward of 40 tokens is only awarded once per path per day, resetting at the same time as the dailies. This is not affected by DR. Meaning, if the path is completed the first time before reset and then again after reset, the bonus reward is still fully awarded.
- Completing the path consecutively triggers the dungeon DR, which reduces the base reward for that path by half until reaching a minimum value. This reduction wears off one hour after the completion of the path. Meaning, the path DR is like a 1 hour condition, where each stack has its own 1 hour duration. It is not removed by daily reset.
Event & Map DR
Another type of Diminishing Returns applies to events in the open world. It affects the amount of coin, experience, karma, and Map Bonus Rewards. Again, ArenaNet will not offer the details of how it works and some of the mechanics changed with the release of Heart of Thorns. Presently, there is no consensus on the specifics, so the following illustrates the community's best understanding:
- Event DR applies when a character repeats the same event multiple times without a break, from as few as two times to as many as 20.
- It also applies to completing multiple events within a single map in core Tyria. However, there's less agreement about whether it's the events, an amount of time spent on the map, or the value of Map Bonus Rewards. It also appears to be variable, triggering with as few as 10 events or 30-45 minutes of time spent doing events.
- It is soulbound, so each character starts fresh for each event or each map.
- As with loot DR, clearing it requires leaving the relevant map or doing other events.
- Event DR can be cleared after completing any other event,
- There is no consensus about how to clear Map DR; some believe it requires an equivalent amount of time spent in another map, some think it requires doing a number of events elsewhere, and others think it only clears with server reset.
- Both event and map DR set in quickly once triggered. It is easy to see its effects by comparing the amount of karma or XP, as well as the absence any boss chests or a decrease of other rewards.
- There is no DR associated with salvaging.
- There is also no evidence that DR applies to any other sources of loot, including PvP rewards, the Mystic Forge, and opening containers.
- Originally, DR was character-based in dungeons. 
- ^ https://forum-en.guildwars2.com/forum/game/gw2/Let-s-Start-the-Karma-DR-Dialogue/page/5#post338355 Jon Peters, GW2 Forums
- ^ John Smith posted that, "There’s virtually no DR active on any given day."
- ^ https://forum-en.guildwars2.com/forum/game/bltc/Stealth-nerf-on-ecto-drops/first#post693957 John Smith, GW2 Forums
- ^ https://forum-en.guildwars2.com/forum/game/dungeons/Dungeon-DR-is-now-account-bound-never-got-it-before-today/first#post319465 Jon Peters, GW2 Forums