https://yamcode.com/why-we-do-....we-love-item-upgrade
World of Warcraft Upgrades and Item Upgrading Upgrades increase the value of certain numeric stats on weapons, armor and rings. Upgrades also boost bonuses like Crit chance and damage from PvE. For instance a weapon that has the upgrade template that ends in % will suffer an attack damage of 3% each time it is upgraded (relative to its previous value). The cost for upgrading items increases when they reach the current level of the item. The cost increases with the item's level. Components Upgrade components can be