WoW Item Upgrades
Item upgrades--more commonly known as "upping"--are an enchantment and Item upgrader Kit (k12.instructure.com) that can be applied to armor and weapons to boost their stats. These upgrades can increase the gauge of an item by a specific amount of points. Their cost increases depending on their rarity.
The melee PvP scene is highly influenced by a perfectly rolled version of armor due to its ability to minimize weapon damage.
Type-restricted upgrades
Upgrades are an essential part of the equipment crafting process. They can enhance the stats of an item and make it stronger or weaker and even provide a bonus effect. They can also alter the appearance of an item upgrading. While certain upgrades are universal, others have special rules for applying to weapons or armor. A bad upgrade item can destroy a weapon that was otherwise excellent, and could even render it useless.
As a general rule you can only upgrade item the equipment you have to the level of its top-level counterpart.