World of Warcraft Item Upgrades
Upgrades to items are a method to boost the stats of an item. Based on the type of upgrade you choose, it can boost an item's Rarity or Mark Level and increase other stats.

The process of upgrading gear in The War Within requires a specified number of Flightstones and Crests, and each item has an upgrade track. Each upgrade increases the cost of the following one by a specific amount.
Item Level
When an item is upgraded, its base stats are increased in value. This is the sum of all the leveled up perks (attack, magic attack and defense). The cost of upgrading items can be high depending on the upgrader and what type of upgrade you choose to perform. This is because of how many perks must be replaced in order for the item to be upgraded.
It can also be used as a gating requirement when queueing for raids, dungeons and scenarios. It also serves to limit the amount of PvP gear players can use since PvP is not available at lower levels. Players can see their average level of items on their character sheet.
Utilizing the level of an item can help players evaluate the strength of equipment when deciding to purchase or sell. It's a sign of the damage and its quality. The item level can also be used to evaluate items when looking at the inventory of a seller.
On PC, you can see the level of the item by pressing ALT or by using the left stick on XB1 or PS4. This will show the full item description, including its value. It is also accessible by hovering an item with the mouse cursor and entering /itemlevel into chat.
There are a variety of theories on the method by which the level of an item is determined. One theory is that the level is a numerical value derived from a formula which calculates how much an item's stats are worth. It takes into consideration the fact that various perks have different value, and also that gems in sockets increase the overall value of the item. This can result in an item's ilvl which is calculated and is often very close to Blizzards actual item level.
It's not the only factor that affects the value of an item. The location of where the item dropped can also alter its stats. For example it can add a level to the item's haste or crit score. This means that items that drop at higher levels will have higher the ilvl than items from lower level instances.
Item Stats
Stats on an item are a significant part of what determines the value of an item for players. The game utilizes them in many ways to encourage players not to restrict themselves to a particular weapon and to motivate them to try out other weapons. The stats of a base weapon are boosted by the weapon's stat modifications which are then boosted by the player's level.
Item upgrades add to that by increasing certain stats of the item. The rarity of an item determines the upgrade cost. A grey or white item for instance, can only be upgraded once however, items with rare tiers can be upgraded several times at more expensive costs.
Another method to alter the stats of an item is to use affixes. They are stat boosts which can be added by the player to an item. The affixes can be used to provide items with extra damage, special abilities (such as the ability to revive dead or reduce cooling downs), or to differentiate them by putting a name on them.
Presently, all affixes are able to be modified by selecting them in the upgrade window and pressing the green button, which is accompanied by circling arrows. This will cost a certain amount of gold and other items. They can also be used as upgrade gauges, just like the other rerolling methods.
In addition to Rerolling affixes and rerolls, players can also choose which stats they want to keep on an item when it is upgraded. The range of stats determined by the item's level. However every item will have at least one stat within the range, unless they are a unique item, or a God Roll from a raid boss.
This is another thing that could be altered by adding the option to upgrade the equipment without rolling the affixes or choosing which stats to enhance. But, like base equipment, this would have to be done on a per-item basis, and the interface for item comparison will not show all the stats that could be either lost or gained at the same time.
Item Luck
The Luck stat for a player adds up to increase the chances of finding items as well as the properties that appear on loot drops, and the intensity of these properties. However, it does not directly impact damage or the ability to upgrade item s. It gives players the chance to upgrade equipment earlier in the game. This is especially beneficial in the early game, because players tend to put the scaling of weapons and defenses over raw damage gains.
Luck can also boost the likelihood of upgrading items at the Blacksmith. This is not to be confused with the Blacksmith’s overall upgrade chances, which increase with each new level of item. It is also possible to be enhanced by using anti-materials like a Scroll of Strength and a Jewel of Blessing.
Weapons, shields, and armor can spawn or be crafted by using the Luck property, with the default value of 40. These items can then be enhanced with golden ingots, spined leather or oak boards (depending on the material of the item) to give +40 Luck, or to increase the Luck of an item up to 140.
Additionally, certain items, such as the Hollow infused weapon can be used to increase the damage dealt by any damage-dealing skill by 5%. These items can be purchased in the shop or crafted with the right ingredients.
Item Failure
Not all upgrades work. However, there are cash shop items that allow players to increase their chance of success or stop themselves from losing an item if the upgrade fails.
The rate of success of an upgrade is shown in the Honing UI. The percentage represents the probability of completing the upgrade successfully and can be enhanced by adding Additional Materials or Special Materials. The chance of success can only be increased as much, and the likelihood that an upgrade will fail can't exceed 100%..
The Luck of an item can affect the success of an upgrade. All items have a base success rate of 25% and every item with Luck increases the chance of success by an additional 5%.
The upgrade overlays of the item are displayed above items in the inventory. This can 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.