Item Quality

All items found in World of Warcraft are given a quality rating that is defined by the item text's color.

Poor Quality (Grey)[]

Poor quality items only drop from mobs or similar looting, such as chests; they are never sold by vendors (except buy-back), are never crafted by professions, and very rarely awarded by quests.

Poor quality pieces of equipment will generally have a minimum level to be able to be equipped, but the benefits that come from them are usually less than those of better quality items, even of a slightly a lower level. Poor quality weapons and armor have no stat bonuses.

If you are just starting WoW, check the gear you find and compare the relevant numbers; some poor quality drops may be better than some of the common quality gear you are using. This will be especially true around level six, when you've just left your beginning area and are starting your village level quests. For example, patchwork cloth armor pieces are typically better than any cloth armor you've seen up to that point.

Poor quality equipment typically does not bind, and has the advantage that it can be used, then traded.

Poor quality items cannot be disenchanted.

Poor quality weapons and armor sell slowly at auction and have a high listing fee. You will probably find that you are better off vending these items.

One particularly important poor quality item, [Noboru's Cudgel], starts a quest.

Useless items dropped by mobs, also known as salvage items, "vendor junk", or "vendor trash" (VT), are poor quality items and are good for one thing and one thing only: to sell to a vendor. This does not mean they are worthless, since some poor quality items can sell for a decent amount of money (at level 70 some items can sell for several gold).

Common Quality (White)[]

Most common quality items are either used for professions, spell reagents, quest items, consumable or are equipment items bought from a vendor, awarded by a low level quest, or are crafted by a profession in the earlier crafting recipes. Common quality weapons and armor usually have no stat bonuses.

Common quality mob drops and purchased items typically do not bind, and have the advantage that they can be used, then traded. Common quality quest awards are typically Bind on Pickup.

Common quality items cannot be disenchanted.

Common quality weapons and armor sell slowly at auction and have a high listing fee. You will probably find that you are better off vending these items.

There is a good market for many common crafting materials. For example, most cloth can be sold at the Auction House for much more than vendors will pay.

Since common quality items are less restricted by binding that better quality items, some common quality equipment items are more valuable than their 'better' counterparts. Bags in particular have this, and some vendor wands may be better than their uncommon quality counterparts.

An item that a trade skill enchantment is enchanted on should usually be a low level common or poor quality cloth item (typically a glove). This is so any character can use the item and so that it does not bind. The exception is when there is a specific item that has the same skill bonus, because then you want to cast on that item so the bonuses stack. (Some folks may prefer the enchantment on a Bind on Equip glove they can't accidentally give away.)

Functionally for the player, grey and white quality items are similar; grey has somewhat lower stats, but neither have bonuses, neither bind (except for quest awards), neither can be disenchanted. White parts items are used in something; in a recipe or for a quest; grey parts items are generally not useful anywhere except to sell to a vendor.

Trivia: the most absolutely useless items in the game are white, not grey. Many quest items have no vendor value, cannot be auctioned, and can only be used within the context of the quest. It is often possible to acquire an excess of these items beyond what the quest requires. If the dropped item has to be transformed, additional drops can be acquired after the transformation, before the turn-in. The excess is useless and can only be kept or destroyed. Examples: the Dwarven mining tools in Mulgore that have to be destroyed for Dwarven_Digging, and the necklace worn by the furbolg chief in eastern Teldrassil from which you have to remove a gem for Ferocitas the Dream Eater. Also, if a spawned mob can drop the item, you may have an extra one drop. Example: in the Draenei Red Snapper quest, you can net your last needed red snapper, have a murloc spawn, and have another red snapper drop - and it's not even edible.

Uncommon Quality (Green)[]

Uncommon items are usually random world drops, with an overall drop rate between 1% and 10% of kills, are crafted by a profession in mid range crafting recipes, or are awarded by a mid level quest. Jewelcrafters have the ability to produce Uncommon quality rings as soon as they receive apprentice training.

Uncommon equipment is usually Bind on Equip, though items dropped from bosses or awarded by quests will generally Bind on Pickup.

Most uncommon quality equipment items can be disenchanted. (See exceptions)

It's a good idea to sell unused green items at the auction house instead of to vendors, or disenchant them for enchanting reagents.

Rare Quality (Blue)[]

Rare quality can also be referred to as Superior quality. Like uncommon items, rare items generally come from world drops, drops from instance bosses, are crafted by a profession in high level crafting recipes, or are awarded by a high level quest.

World drops are randomly dropped from almost any mob in the world (within a given level range) and as a result cannot be farmed; The only effective way to get your hands on one you want is to seek out another player who was lucky enough to find it (the auction house helps a lot with this). These items will usually Bind on Equip.
Instance drops are typically found on bosses in instances; such drops are almost always exclusive to that boss (example: the [Illusionary Rod] that drops off of Arcanist Doan in the Scarlet Monastery only drops off of Doan). Most of these items will Bind on Pickup, so take care when rolling for them.

Most rare quality equipment items can be disenchanted. (See exceptions)

Epic Quality (Purple)[]

Epic quality items are quite rare and in general have much better bonuses than other items of their required level. Epic items also usually have some sort of passive or on-use effect attached to them or some kind of proc. Like rare items, there are a few BoE world drop epics. Most BoP epic items are found in raid instances, end bosses in heroic mode instances or top level recipes for tradeskills.

Most epic quality equipment items can be disenchanted. (See exceptions)

Legendary Quality (Orange)[]

Legendary items, such as [Sulfuras, Hand of Ragnaros] and [Thunderfury, Blessed Blade of the Windseeker], are a step up from epic items and are truly exceptional. These items are extremely rare and very few people have them. These items usually require the completion of a long chain of quests, as it is with Thunderfury or Ashbringer, but this is not always the case.

Legendary items cannot be disenchanted.

Artifact Quality (Light Gold)[]

Artifact items are objects of unimaginable power and are also not yet implemented (for player characters, at least). It has been speculated Frostmourne and Book of Medivh will be an Artifact. Artifact items are speculated to end up being "Unique" per server. Note that, while this is generally already true of the [Black Qiraji Resonating Crystal], it is technically possible for more than one person to acquire the Crystal if they have [The Scepter of the Shifting Sands] and ring the gong within ten hours of the initial ringing. Additionally, the Crystal's nondescript place in lore (it is legendary due to the limited quantity available) gives weight to the argument that it is not in the same league as "Artifact" items.