World of Warcraft Item Upgrades
Item upgrades can be used to improve the stats of an item. Depending on the upgrade type it can raise an item's Mark level or Rarity, as well as boost other stats.
Each item has a track for upgrading it. Each upgrade increases the cost of the following one by a certain amount.
Item Level
When an item gets upgraded, its base stats are increased in value. The value is the sum of all of the perks that are leveled up (attack magic attack and defense). Upgrades can be expensive depending on who you hire and what you do. This is due to the sheer number of perks that must be altered to upgrade an item.
It is also used as a gating requirement when queueing for raids, dungeons and scenarios. It also serves to limit how much PvP gear players can wear, since PvP is limited at lower levels. Players can view their average item level in their character sheet.
When deciding whether to purchase or sell gear players can evaluate the item level. It's a sign of the damage and its quality. Comparing items in the inventory of a seller is possible using the item's level.
The level of the item can be seen by pressing the ALT key on a PC or using the left stick (L3) on XB1 and PS4. This will show the item's full description, including ilvl. You can also find it by hovering over an item and typing /itemlevel into chat.
There are a variety of theories on the method by which the level of an item is determined. One theory says that the level of an item is determined by an equation that determines the worth of an item's stats really are. It takes into consideration that different advantages are valued differently and that gems in the sockets increase the value of the item. This can lead to an item's ilvl calculated, which is usually very close to Blizzard's actual item level.
However, this is not the only factor which can affect an item's ilvl since the size of the area the item dropped in can alter the value of its stats, for example by adding an additional level to its crit rating or haste rating. Items that drop in higher-level situations will have higher ilvl.
Item Stats
Item stats can make or break an item for players. The game uses them in many ways to encourage players to not limit themselves to a single weapon, and to encourage them to try out other weapons. The base stats of a weapon are boosted by the weapon's stat modifications that are in turn increased by the player's skill.
The upgrades to an item can boost its stats. The rarity of an item determines the cost of upgrading. For instance, a gray or white item can only be upgraded once, while an item with rare tiers will be upgraded several times with higher prices.
Another way to change the stats on an item is to use affixes. They are stat boosts that can be added by the player to an item. Affixes can be used to give the item additional damage, add a special capability to the item (such as reviving dead or cutting down the cooldowns) or make the item unique by giving an exclusive name to the item.
All affixes are currently re-rolled by selecting them in the upgrade window pressing the green button. This procedure will cost the player a specific amount of gold and other items which can be added to the upgrade gauge in the same way as the other options for rerolling.
Players can choose to upgrade an item with specific stats, or reroll the affixes. The possible ranges of stats for an item are based on the item level, but every item is guaranteed to have at minimum one stat within that range, unless it is an item that is unique or a God roll from a boss of a raid.
Another thing that could be changed is the option to upgrade equipment without having to reroll the attaches, or select which stats to enhance. But as with base equipment, this would need to be carried out on a per-item basis and the interface for comparing items will not show all the stats that could be that were gained or lost at the same time.
Item Luck
The Luck stat of a player boosts the chance of finding items, the properties that are generated by loot, and the strength of these properties. However, it does not directly impact damage or the ability to upgrade item s. It simply gives players a chance to upgrade their equipment earlier in the game, and is therefore more useful in the initial game run as opposed to later ones, since most players prefer more powerful weapon scaling and defenses over damage gains.
Luck can also increase the likelihood of upgrading items at the Blacksmith. This is not to be confused with the Blacksmith's overall upgrade chances that increase with each level of the item. These can also be increased with the use of anti-materials, such as a Scroll of Strength and a Jewel of Blessing.

Armor, shields and weapons can be made or spawn with the Luck property, which has a default value of 40. These items can be enhanced by golden ingots, spined leather, or oak boards (depending on the item's material type) to grant a further +40 Luck or to boost the existing Luck of an item, up to 140.
Furthermore there are certain items, like the Hollow weapon that is infused with hollow can be used to increase the damage of any damage-dealing skill by 5percent. These items can be bought at the store, or they can be made using the correct ingredients.
Item Failure
Upgrades to items can be costly and not all upgrades will succeed. However, there are some cash shop items which allow players to increase their chances of success or even prevent them from losing an item if the upgrade fails.
The success rate of an upgrade can be seen in the Honing UI. The percentage represents the probability of successfully upgrading that item and it can be increased by adding Additional Materials or Special Materials. The chance of success can only be increased as high, and the probability that an upgrade will fail cannot exceed 100%..
The success of an item upgrades is also influenced by the luck of the item. All items have an average success rate of 25%, and every item that has Luck increases the chance of success by 5%.
The upgrade overlays for items are rendered above the items in the inventory. This could obscure enchantment effects and other effects. If you wish to disable the upgrade overlays, the config option decoration.renderUpgradeOverlays can be set to False in the Item Upgrader CORE client config.