World of Warcraft Item Upgrades
Upgrades to items can be used to boost the stats of an item. Depending on the upgrade type it could raise an item's Mark level or Rarity and boost additional stats.
Upgrading equipment in The War Within requires a specified number of Flightstones and Crests, and each item has an upgrade track. Each upgrade increases the price of the next item by a specified amount.
Item Level
The value of an item's stats base increase when it is upgraded. This is the sum of all of an item's leveled-up perks (attack magic attack and defense). Upgrading items can be expensive, depending on the upgrader and the kind of upgrade you decide to make. This is due to how many perks need to be replaced in order for the item to be upgraded.
It is also used to enforce gating requirements when queueing for dungeons, raids and scenarios. It can also be used to determine a gating condition when waiting for dungeons, raids and scenarios, and to limit the amount of PvP gear players can wear (since PvP is limited to the lower levels). The average item level can be found in the character sheet.
Using the item level will allow players to compare the power of equipment when deciding to purchase or sell. It's a sign of the damage and its quality. The level of the item can be used to evaluate items when evaluating the inventory of a seller.
The item level can be seen by pressing the ALT key on PC or using the left stick (L3) on XB1 and PS4. The item will be displayed with its full description, including the ilvl. You can also locate it by hovering over an item and typing in /itemlevel chat.
There are several theories about the method by which the level of an item is calculated. One theory is that the level is a number derived from a formula that determines the value of an item's stats are worth. It takes into consideration that different advantages are valued differently and that gems in the sockets boost the value of the item. This process can result in a calculated amount for the item's ilvl, which is usually quite close to the actual Blizzard level of the item.
However, this isn't the only factor that determines the ilvl of an item, since the size of the area the item is dropped into can alter the value of its stats, for example by adding a level to its crit rating or haste rating. Items that drop in higher-level situations will have a higher value.
Item Stats
Item stats are a big part of what makes or breaks an item for players. The game utilizes them in many ways to encourage players not to limit themselves to one weapon and to encourage them to try out other weapons. The stat modifications of weapons boost base stats. These stat mods are then enhanced by the player's level.
The upgrades to an item can increase the stats of an item. The cost of upgrades is determined by the rarity of the item. For instance, a gray or white item can only be upgraded once, whereas an item with rare tiers can be upgraded many times, at higher costs.
Another way to change the stats on an item is through affixes. They are stat boosts which can be added by the player to an item. The affixes could do things like give the item extra damage, or give a specific ability to the item (such as reviving dead or reducing the cooldowns) or make the item unique by putting a special name to the item.
item upgrade are being re-rolled right now by selecting them in the upgrade window, pressing the green button. This will cost a specific amount in gold and items. They can also be used as upgrade gauges similar to other methods of rerolling.
Players can choose to upgrade an item to specific stats, or reroll the affixes. The range of stats is determined by the item's level. However, all items will have at least one stat within that range unless they are an exclusive item or an item that has a God Roll from a raid boss.

Another thing that could be altered by adding an option to upgrade the equipment without rolling the affixes, or selecting which stats to increase. Like 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 can increase the chance of finding items, the properties that are spawned by loot and the intensity of these properties. However, it doesn't directly impact damage or the ability to upgrade items. It gives the player the chance to upgrade their equipment earlier in the game. This is more advantageous in early game runs because players tend to put the scaling of weapons and defenses over raw damage gains.
Luck can also increase the chance of upgrading items at the Blacksmith. This should not be confused with the Blacksmith's overall chance of upgrading, which increases with each level of the item and can be further increased by using an anti-material such as a Scroll of Strength or a Jewel of Blessing.
The shields, armor, and weapons have the default Luck value of 40. These items can be enhanced with golden ingots, or spined leather (depending on their material type) to add another 40 luck or to increase the Luck of an item up to 140.
Additionally some items, such as the Hollow weapon, which is infused with Hollow, can be equipped to increase the damage dealt by any damage-dealing skill by 5percent. These items can be found in the shop or created with the right ingredients.
Item Failure
Not all upgrades are successful. Cash shop items can be used to increase the chance of success of an upgrade or to prevent players from losing their items if it fails.
When you upgrade an item the success rate is displayed in the Honing UI. The percentage represents the chance of successfully upgrading that item and can be enhanced by adding Additional Materials or Special Materials. The percentage of success can only be increased so much, and the likelihood that an upgrade will fail can't exceed 100%..
The Luck of an item may affect the success of an upgrade. All items have a success rate of 25%, and each item with Luck increases the chance of success by five percent.
The upgrade overlays of the item are rendered above items in the inventory. This may cause obscurity to enchantment effects or 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.