World of Warcraft Item Upgrades
The upgrade of an item can be used to boost the stats of an item. Depending on the upgrade type it could boost an item's Mark Level or Rarity, and also boost other stats.
The process of upgrading equipment in The War Within requires a certain number of Flightstones and Crests Each item has an upgrade track. Each upgrade increases the cost of the following one by a specific amount.

Item Level
The value of an item's stats base increases as it is upgraded. This 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 decide to do. This is due to the sheer number of perks that must be changed in order to upgrade an item.
Item level is a widely used measure of power, and can be found on all item tooltips. It also serves to determine a gating condition when waiting to queue for dungeons and scenarios and raids, and to limit the amount of PvP gear a player can wear (since PvP is capped at the lower levels). The average level of the item is listed on the character sheet.
The level of an item will allow players to compare the potency of gear when they decide to buy or sell. It's a sign of the item's condition and its quality. Comparing items in the inventory of a seller is possible using the item level.
The item level can be checked by pressing the ALT key on your PC or using the left stick (L3) on XB1 and PS4. This will display the item's full description, including the ilvl. You can also locate it by hovering over an item and typing in /itemlevel chat.
There are many theories about how the level of an item is calculated. item upgrade is that the item level is a number derived from a formula that determines the amount an item's stats are worth. It takes into consideration that different benefits are valued differently and that gems found in sockets increase the item's value. This can lead to an item's ilvl which is calculated and is typically very close to Blizzard's real item level.
However, this is not the only factor which can affect an item's ilvl because the size of the area the item is dropped into can change the value of its stats, such as by adding an additional level to its crit rating or haste rating. This means that items dropped at higher levels will have higher ilvl than those from lower-level instances.
Item Stats
The stats of an item are a major element in what determines the value of an item for players. The game utilizes them in many ways to encourage players to not restrict themselves to a particular weapon, and to encourage players to experiment with other weapons. The base stats on a weapon are enhanced by the weapon's stat mods that are in turn boosted by the player's level.
Item upgrades add to that by increasing certain stats on the item. The upgrade costs are determined by the rarity of the item. For example, a grey or white item can only be upgraded once, while an item with the rare levels will be upgraded multiple times with higher prices.
Affixes can also be used to alter the stats of an item. They are stat boosts that can be added by the player to an item. Affixes can do things like give the item additional damage, or add a unique ability to the item (such as reviving dead or decreasing the cooldowns) or make the item unique by adding an exclusive name to the item.
All affixes are currently re-rolled by selecting them in the upgrade window pressing the green button. This process will cost the player a specific amount of gold and items which can be used to add to the upgrade gauge in the same manner as other rerolling options.
Players can choose to upgrade an item to specific stats, or reroll affixes. The range of stats determined by the item's level. However every item will have at least one stat in the same range, unless it's a unique item, or an item that has a God Roll from a raid boss.
Another thing that could be changed by adding the option to upgrade the equipment without having to reroll the affixes, or selecting which stats to enhance. As with base equipment, it will have to be done per item, and the interface for item comparison wouldn't display all possible stats simultaneously.
Item Luck
The Luck stat of a player boosts the likelihood of locating items, the properties that are generated by loot, and the strength of these properties. However, it doesn't directly impact damage or the ability to upgrade items. It simply gives players the possibility to obtain better equipment earlier in the game and is thus more useful in the initial game run as opposed to later ones, since most players prefer greater weapon scaling and defense over the raw damage gain.
Luck can also increase the chances of upgrading items at the Blacksmith. This is not to confuse with the Blacksmith's overall upgrade chances, which increase with each new level of item. It is also possible to be increased with the use of anti-materials like a Scroll of Strength and a Jewel of Blessing.
Armor, shields and weapons come with the default Luck value of 40. These items can then be upgraded with golden ingots, spined leather, or oak boards (depending on the item's material type) to grant a further +40 Luck or to boost the Luck of an item, up to 140.
Certain items, like the weapon with Hollow-infused components, can also be equipped to increase the damage dealt by any skill that deals damage by five percent. These items can be found in the shop or crafted using the right ingredients.
Item Failure
Upgrades to items can be expensive and not every upgrade will be successful. However, there are some cash shop items that allow players to increase their success rate or prevent themselves from losing an item if the upgrade is unsuccessful.
When you upgrade an item, the rate of success is displayed in the Honing UI. The percentage indicates the probability of successfully upgrading the item. This can be increased by using Additional Materials or Special materials. There are limitations on how much the success rates can be improved and the chance of an upgrade failing cannot exceed 100%..
The performance of an can be affected by the luck of the item. Every item has an average success rate of 25%, and every item with Luck increases that chance by five percent.
Note that upgrades to items are rendered above the inventory items therefore enchantment glints and other effects could be masked by them. 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.