From GoesToEleven
This article discusses the way WoW handles instances. It first explains the basic concepts of instances and instance IDs. It then continues to explore the potential pitfalls inherent to this system.
It's actually not all that difficult, but in play a lot of confusion can arise.
The original version of this guide can be found here. All discussion should be held there as well.
Instances
In World of Warcraft, all characters are in the same "world". If one character walks along the road from Stormwind towards Goldshire and another character walks from Goldshire towards Stormwind, they will encounter each other.
Compare this with dungeons and battlegrounds and the like, which are instanced. Two persons, both in, say, the ballroom of Karazhan, do not necessarily see each other.
It is called an "instance" because there can be multiple copies (instances) of the same place on the same realm. When you (and your group) enter an instance through an instance portal, a personal copy of the area is made. Only you and your group members are in this particular copy.
Instances and groups
An instance is associated with you. Once you group with others, things get confusing.
Suppose that Alice and Bob are not group, and each walks into the Deadmines. Clearly, they're in different instances of the Deadmines. They can't see each other.
Now Alice and Bob group while they're in the Deadmines. Now what? They're still in different instances.
But how do they get the same instance so they can actually play together? One of them, the one who is not the group leader, has to leave his or her dungeon, and then reenter it. Now they'll be in the same instance.
Any progress in an instance is saved. So if Alice killed a bunch of Defias on her own and then moves out and back in, those Defias are still dead.
Alice and Bob are in separate instances and only Alice kills stuff. She invites (lazy) Bob who accepts. This makes Alice group leader. Bob leaves his instance. He then reenters the Deadmines, thereby entering Alice's instance of the Deadmines. In Alice's instance, there's a bunch of Defias dead. Those stay dead, saving Bob some effort (but also any quest items, loot and XP that Alice might've gotten so far.)
In other words
Another version of the above:
- Alice and Bob are not grouped in deadmines. Both are soft-saved. Then Alice invites Bob. Alice now is the party leader and wants to join Bob's instance because Bob isn't too far yet into it or whatever. What to do?
- Alice leaves instance
- Alice makes Bob leader
- Alice enters instance
- Alice is the party leader and Bob wants to join her instance. Both are soft-saved.
- Bob leaves instance
- Bob enters instance
- Alice is the party leader, hasn't been in an instance, and invites Bob who is in the instance already.
- Alice can just enter since she is not soft-saved. She will join Bob's instance.
Instance IDs & How to check them
Also called "raid ID", an instance ID is a number that says which particular instance of a dungeon you're associated with ("saved to"). You can check the instances you're saved to and their IDs with the console command /raidinfo. You can also access this info via the Social panel ("o" by default), then going to "raid" and finally pushing "raid info" in the top right corner.
All members in your group/raid should be in the same instance and have the same ID for that dungeon. If not, your party is spread across multiple instances and won't all see every group/raid member.
Instance resets
Source: http://www.wowwiki.com/Instance_reset
There are two ways to reset this kind of saving and the associated progress. A "soft reset" is when all party members leave the instance for at least 30 minutes. This causes all trash mobs to respawn. This can be useful to reset boss fights that are bugged or something.
A "hard reset" is when all party members leave the instance and the party leader performs a manual reset. This is done by right-clicking on his own portrait and clicking the "Reset Instance" button. This totally restarts the instance, respawning all mobs including bosses.
The first constraint to hard resets is that you can only perform 5 hard resets per instance per hour. This was done to prevent farming of specific encounters or resource nodes.
The second constraint is that Heroic mode instances and Raid instances cannot be hard reset manually. Instead, these instances reset automatically on set times. These are called "reset timers" or "raid timers" and are specific to the dungeon in question.
- Heroic mode 5-mans reset every night at 4 AM.
- We assume Normal mode 5-man instances are hard reset every night at 4AM, just like Heroic modes.
- Vanilla raids were all over the place, ranging from once every 3 days to each Wednesday. See the in-game calendar for specifics.
- All TBC raids are reset on Wednesday 4 AM (or during the maintenance if there is any), except for Zul'Aman which is reset every 3 days at 8 AM.
- All Wrath raids are reset on Wednesday 4 AM (or during the maintenance if there is any). Of special interest is the Vault of Archavon, which is reset like all other Wrath raids. You can only enter it though if your faction has won the last Wintergrasp battle.
More about instance saving and the pitfalls
Killing a boss will "hard" save you to the instance.
There are some events that save you to an instance, even before you kill a boss. Notably, this is done in Violet Hold, where you otherwise could just keep resetting the instance until you got an easy first boss.
If you're saved to an instance of a dungeon, you will always enter that instance. You can only change this by hard resetting the instance. This leads to logical conclusion that once you're saved to a Heroic mode instance or a raid instance, you can not change your instance until it is hard reset by the instance timer.
Things get a little trickier if you're not saved to an instance of a dungeon, and some of your group (or raid) members are.
If you're not saved but your party/raid leader is, you will be saved to your raid leader's instance as soon as you enter the dungeon.
There's no way to see to which instances another character has been saved to. If you join a group/raid where somebody else is group/raid leader you depend on that person's honesty whether you'll be saved or not. An additional potential pitfall is when party/raid leaders are switched. The original leader, who invited you, might not have been saved to an instance, but once the leader is switched, old bets are off. Therefore, be careful when joining PUGs.
If you are saved to a GT11 instance, be extra cautious. Another character can "steal" your (GT11's) instance ID by inviting you to their group, making you raid leader, and entering the dungeon.
