WoW Upgrades - The Item Upgrader
Upgrades will give you a boost to certain stats. Each upgrade increases the level of an item by 3. Each upgrade also increases an unspecified substat.
The more modernized gear generally has a greater value for trade as long as it meets low requirements (like the FB sorc's shield) or very high stat variance (like Eth titan weapons). These types of gear get less value from upgrading due to the necessity to roll for a perfect version.
Recycle Points
The upgrader for items allows players to upgrade gear to a higher level by providing the appropriate currency to the NPC. Upgrades can be made on any type of armor or weapons. The item used to upgrade the item will be consumed and can't be used again. Upgrades can also be used to create enhancements.
You can upgrade your gear at any time by visiting the upgrader in any major city. item upgrading is recommended that you visit the upgrader at least once every few weeks, to ensure that your equipment is up to date.
The cost of upgrades will depend on the current level of the item being upgraded but they will always be cheaper than purchasing new equipment from other sources. For example upgrading a chest piece from Benthic to ilvl 385 will cost 20 recycle points, purchasing a similar piece from another player will costs 105.

Valorstones
Upgrades are items that can be used to purchase weapon, armor, tool, and accessory upgrades. They can be purchased by players from NPCs of item upgraders for a variety of currencies. They can also find them on random treasure lists. Once an upgrade has been purchased, it can be applied to any weapon or tool using a button, which will display a preview of the item when it is upgraded if the player has sufficient materials.
The cost of upgrades varies based on the item slot and the current level of the item and the weapon's price is higher than gloves or bracers, for instance. Each upgrade cost 15 Flightstones and a variety of crests, with certain upgrades offering discounts to reduce the cost of the Flightstones or crests used. Once an item has been upgraded to a certain amount, it can be downgraded and sold to the upgrader at a lower price.
Upgraders for items are available in many places on the main island and some outposts. The NPCs provide an upgrade discount as well as a chance to obtain a new upgrade recipe. The upgrade discount increases with the number of items being upgraded. It can also be increased by having players complete specific achievements or quests.
Icewind Dale does not have an item upgrader at the beginning, unlike Cromwell from Baldur's Gate II. Instead the NPCs that can be used to upgrade must be acquired through several methods that are both an improvement but also a drawback.
In Season 3, a number of new features have been added to the upgrade system. After an upgrade has been completed to a specific level for an armor slot upgrading other items to the same item level, will cost less. This is even if the items are from a different set of gear.
The discount applies to all accounts. The amount of Harbinger Crests needed to upgrade is reduced also, but is only available when certain milestones are achieved.
Crests
Players have a number of choices when it comes to upgrading their equipment in WoW. They can make use of Flightstones which are a common upgrade currency that is accessible to all players, or crests that are more specific and used to upgrade specific item levels. Crests are an essential part of the Dragonflight gear progression system that was introduced in 10.1 and are available in 4 ranks.
The first thing to note is that crests can only be used on gear of a specific rank, and that each rank has different requirements for its upgrade path. The simplest and easiest upgrade is 15 crests. The most complex upgrade could require as much as 20 crests, based on the kind of equipment that is being upgraded.
Players can earn crests by finishing content at the appropriate level, whether that involves walking around and engaging in outdoor activities for lower-tier gear, raids or dungeons of any difficulty for higher-tier items or Mythic+ heroic raid bosses or dungeons to obtain endgame gear. The crests can later be exchanged at an upgrader NPC, like Cuzolth in Dornogal or Vaskarn in Valdrakken to obtain the appropriate upgrade paths and steps.
The new currency system isn't complicated to use, however it does bring some modifications to the upgrade process. When a piece of equipment has reached the highest level of upgrade for any rank (Explorer or Adventurer) it is no longer required to purchase Flightstones. This change lets players upgrade their gear to the highest possible ilvl on all of their characters instead of relying on seasonal loot.
It's also important to use crests with care, since they are only used for one purpose. For instance, it's best to make use of all your Whelpling-rank crests on the top equipment available and save Drake and Wyrm crests for the next batch of upgrades you plan to make. This is especially relevant for rings and trinkets that take up multiple slots on the character, which can only be eligible to benefit from the account-wide discount if all of the slots are full of high-quality equipment.