Cooldown

A period of wait time before a spell, ability or item power can be used after a prior spell, ability, or item power.

For example:

• The time it takes to recharge after a spell has been cast or an ability or item power has started being used. You will not be allowed to cast another spell for the duration of the cooldown period. This is not the cast time, and usually the cast time of a spell or ability is longer than the global cooldown, which means you can begin your next spell immediately after the cast is finished.
• A  [Hearthstone] has a 60 minute cooldown time.

Shared cooldown

A shared cooldown is when some spell, item or ability prevents usage of certain others while it is cooling down. It effectively applies the same cooldown to all those that it shares cooldown with.

It is important to know if a spell or item has a shared cooldown, since that is much more limiting than an isolated cooldown. This usually means that you must choose wisely which to use, since you cannot use all within a short time period. For instance, many potions share cooldown with other potions, and some of the warrior's abilities share cooldown, as well as hunter traps.

Global cooldown

A global or universal cooldown, frequently shortened to GCD, is the cooldown which starts every time you start to cast a spell, and it affects all of your class spells. There are exceptions to this, however, as noted below. The basic rule of thumb is that if the spell affects the casting of the next spell, it will not activate the global cooldown.

If the spell has a casting time less than the global cooldown (or instant cast), you generally have to wait the remainder of the global cooldown. If a spell with casting time is interrupted before it has finished casting, the global cooldown will be canceled, meaning you can start casting a new one immediately.

The global cooldown is generally 1.5 seconds for all classes except rogues and cat form druids, whose abilities are mostly one second global cooldown. Items with a global cooldown of 1.5 will still apply to rogues and cat form druids.

Abilities noted for not affecting nor being affected by the global cooldown:

• Mage's [Counterspell]
• Paladin's Judgement
• Paladin's [Divine Favor]
• Priest's [Inner Focus]
• Troll's [Berserking]
• Shaman and Druid's [Nature's Swiftness]

Cooldown and usage theory

The cooldown determines how often something (spell, ability, or item) may be used. Specifically, it has an inverse relationship to how many times per fight it may be used.

For example, a druid should never participate in the post-encounter resurrection. The druid resurrection spell is on a 30 minute timer and should be used in emergencies only, such as when it can prevent a wipe.

Here's a rough guide to help with when to burn a cooldown:

Cooldown length		When usable
1.5 sec	GCD	Spammable at will
90 sec	common	Usable whenever desired
3 min	common	Usable each battle, sometimes several times during a boss fight
10 min	mildly long	Usable on most tough miniboss fights
30 min	long	Usable at calculated times and emergencies

Item cooldowns

Items with cooldowns are simply items that have limit on how often you can use them.

For example  [Major Healing Potion] has a 2 minute cooldown, so it can be used just once every 2 minutes. The average cooldown is 2 or 5 minutes, but they range from 10 seconds to 3 hours (like [Signet of Expertise]) to 3 days at the longest. These items can be equipped in a variety of slots or used from the backpack.

Most consumable items have a shared cooldown and some profession-crafting recipes have very long cooldowns on the order of days (like 3 days for [Salt Shaker]).