WoW Upgrades - The Item Upgrader
Upgrades give a guaranteed boost to specific stats. Each upgrade increases item level by +3. Each upgrade also increases a random substat.
The upgraded gear is usually more useful, unless the item has a low requirement by nature (like FB sorc shields) or has a high variance in stats (like the eth Titan weapons). These types of gear get less value from upgrading due to the need to roll for a perfect model.
Recycle Points
The item upgrader lets players upgrade their gear by transferring the currency to an NPC. item upgrading can be applied to any kind of weapon or armor. However, the item that is used to upgrade will remain in use for a long time and can't be used again. Upgrades can be used to create enchantments.
The upgrader is located in all major cities, and can be visited at any time to upgrade your equipment. To keep your gear up-to-date, it is recommended that you visit the upgrader each several weeks.
Upgrades will cost more, based on the level of the item however they'll always be cheaper than buying new equipment. For instance upgrading a chest piece from Benthic to ilvl 385 will cost 20 recycle points, while purchasing the same item from another player will cost 105.
Valorstones
Upgrades are items that can be used to upgrade tools, armor, weapon and accessory upgrades. Players can purchase them through NPCs who sell upgrades to item owners for a variety of currencies. They are also available on random treasure lists. Once purchased, an upgrade is able to be used on any tool, weapon or armor. The button will show the preview of an item's next upgrade level if there are enough materials.
The cost of upgrades varies based on the item slot and the current level of the item, with weapons costing more than gloves or bracers, for instance. Each upgrade cost 15 Flightstones and a number of crests, with some upgrades having a discount to reduce the cost of the Flightstones or the crests used. After an item has been upgraded to a certain amount and is degraded, it can be sold and returned to the upgrader for a lesser amount of both currencies.
Upgraders for items can be found in many places, including the main island as well as some outposts. The NPCs provide an upgrade discount and a chance to acquire a new upgrade recipe. The upgrade discount increases when more items are upgraded. It can also be increased by having players complete certain achievements or quests.
Icewind Dale does not have an item upgrader at the beginning unlike Cromwell from Baldur's gate II. The NPCs that can assist with upgrades are available only through a variety means. This is both a positive and a disadvantage.
In Season 3, several 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 applies regardless of whether the items come from an entirely different set of gear.

The discount applies to all accounts. The amount of Harbinger Crests required to upgrade is also reduced and is not available until players have reached certain achievement milestones.
Crests
Players have several choices when it comes to upgrading their gear in WoW. Flightstones are an item that is available to everyone for upgrading. Crests are more specialized, and are used during specific item level upgrades. Crests are the main component of the Dragonflight gear progression system, which was introduced in 10.1 and are available in 4 ranks.
The first thing to remember is that the crests can only be purchased for equipment that is with a certain rank. Each rank comes with an upgrade path that is different. The simplest and simplest upgrade route costs 15 crests while the most complicated can require as much as 20 crests based on the type of equipment that is being upgraded.
Players can earn crests through working through content that is of the appropriate level, which involves walking around and performing outdoor activities for gear of lower tiers, dungeons or raids of all difficulties for higher-tier items or Mythic+ heroic raid bosses and dungeons to obtain endgame gear. These crests can then be exchanged at an upgrader NPC, such as Cuzolth in Dornogal or Vaskarn in Valdrakken to obtain the appropriate upgrade routes and steps.
The new currency system isn't difficult to use, however it does bring some changes to the upgrade process. When a piece of equipment attains the highest level of upgrade for any rank (Explorer or Adventurer) it is no longer required to purchase Flightstones. item upgrading allows players to upgrade their equipment to the highest level possible for all their characters, instead of relying on seasonal loot.
It's also important to use crests in a wise manner, as they only have one use. For instance, it's a good idea to use all of your Whelpling-rank crests on the top equipment you have, and then save Drake and Wyrm crests to use for the next set of upgrades you plan on making. This is particularly true for items like trinkets and rings that occupy multiple slots on the character which can only be eligible to avail the discount for all accounts when all slots are filled with high-quality gear.