Heroic mode

Heroic mode (often abbreviated to Heroic or simply HC) refers to a dungeon difficulty setting. This setting is accessed from the party or raid leader's portrait menu; currently the only other difficulty setting is normal mode (the default setting). Depending on expansion and dungeon type (5-player or raid), the setting has different effects and requirements. For all heroic mode dungeons mobs and bosses have more HP, hit harder, and have additional or more potent skills. Heroic-mode bosses drop better quality equipment than their normal-mode counterparts as well as currency tokens used to purchase epic equipment from vendors.

Heroic mode dungeons are on a lockout timer much like raids, and can only be run once a day per character. Each dungeon is on an independent timer, however, so a character could run as many as 15 heroic mode instances per day. Heroic timers are reset daily at 9:00 A.M. server time for US servers, and 08:00 A.M. server time for European servers. The daily random heroic resets at the same time as other dailies, generally between 2-4 A.M. realm time.

Heroic dungeons introduced in and  don't require an attunement, but do require all characters in the group to be level 80 for  and level 85 for.

The Burning Crusade
Each of the 5-player dungeons introduced in the World of Warcraft: The Burning Crusade expansion pack may be run on heroic mode if every member of the party has obtained the appropriate key. These keys are purchased from the faction quartermaster of the faction corresponding to the instance once reaching. At introduction the keys required, but this was reduced in later patches to allow easier access to the heroic modes. Magister's Terrace, which was introduced later with patch 2.4, did not use a purchased key. To obtain this key players needed to simply complete a quest which involved killing the final boss of the instance in normal mode.

Some heroic mode instances share loot with their normal-mode counterparts, while some do not. For example, items that drop in a level 70 normal instance like Shattered Halls will also drop in the heroic mode. However a lower-level instance like Hellfire Ramparts will have completely different items in normal and heroic mode. For the instance where loot is shared there are also additional items that only drop in the heroic mode. These items are of higher quality than the other items. Each boss in a heroic dungeon may drop an epic gem. The last boss always drops one epic item in addition to a Badge of Justice.

Each key requires reputation with the respective faction. (Lowered from in patch 2.3.)

Wrath of the Lich King
With the second expansion, heroic mode was extended to raids. The key requirements were not included on instances, instead heroic mode is available to all players at 80. The token system used in TBC heroics was considered successful, new tokens were added for the various "tiers" of wrath heroics and raids. For example, the same tokens drop in heroic 5-players and the first-tier 10-player raids, while a different token drops in the first tier 25-player raids and second-tier 10-player raids. A third token drops in second-tier 25-player raids, and will presumably drop in the third-tier 10-player raids when implemented.

Before Patch 3.2.0, Heroic mode raids, unlike their instance counterparts, did not dictate difficulty. Instead 10-player raids were considered "normal" mode, and 25-player raids to be "heroic". Heroic raids are not intended to be "harder" than the 10-player version of the same raid, instead simply tuned for the larger number of players. Heroic raids do still drop higher quality equipment than the normal-mode counterparts, by the logic that it is more difficult to form a good 25-player group. The currency tokens dropped in each mode can be used to buy items of similar quality to the boss-dropped items.

Patch 3.2.0 did away with this setting, other than showing up in achievements, in favor of the following:
 * Dungeon difficulty:
 * 5-player heroic mode for the Heroic mode instances.
 * Raid difficulty:
 * 10-player heroic mode for the Heroic mode (10-player raid).
 * 25-player heroic mode for the Heroic mode (25-player raid).

In, heroic mode dungeons have the following relative difficulty.

Source: Poll Results For: "What Heroic Dungeon is the Most Challenging?"

Heroic Mode; Violet Hold, located within Dalaran, is commonly considered the easiest of all Northrend Heroic Instances. This is because it can be completed in under 20 minutes on average by those with even minor Heroic Instance Skills. Its low difficulty and low Reputation of 1300 makes it commonly a very casual Heroic Instance.

Cataclysm
Bosses in heroic cataclysm instances award Justice Points. By using the dungeon finder, players can gain an additional 70 Valor Points per day.

Daily heroic
Patch 2.3.0 introduced daily quests for heroic dungeons. These daily quests, referred to as "daily heroics", involved killing the final boss in a dungeon on heroic mode, and gave additional in  or  in  and money as a reward.

Players were able to earn extra Justice Points and gold for the first random WotLK heroic dungeon they complete that day, but the daily heroic quests were removed in patch 3.3.0, however the  daily heroic quests still exist.

Random Cataclysm dungeons yield Valor Points the first time you run them each day.