WoW Upgrades - The Item Upgrader
Upgrades can give you an increase in specific statistics. Each upgrade boosts the level of an item by 3. A random substat is also added to every upgrade.

The upgraded gear typically has a more value in trade, unless it has inherently low requirements (like the FB shield of the sorc) or has a high stat variance (like the eth titan weapons). Upgrades aren't as valuable for the latter because of the requirement to roll an exact version.
Recycle Points
The item upgrader allows players to upgrade their gear by giving the currency to an NPC. Upgrades can be applied to any kind of armor or weapon. However, the item used to upgrade will be consumed forever and will not be able to 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 current it is recommended you visit the upgrader each several weeks.
The cost of upgrades will vary based on the current item level of the gear being upgraded but they will always be less expensive than buying new gear from other sources. For instance, upgrading a chest piece from Benthic to 385 levels will cost 20 recycle points while buying a similar item from a different player will cost 105.
Valorstones
Upgrades are functional items that are used to level up weapons tools, armor, and accessories. They can be purchased by players through NPCs who sell upgrades to item owners for a variety of currencies. They are also available on random treasure lists. Once an upgrade is purchased, it can be applied to any weapon or tool using the help of button, which displays a preview of the item at the next upgrade level when the player has enough materials.
Upgrade costs differ based on the slot of the item and the current item level. For instance, weapons will cost more than gloves, bracers or bracers. upgrade item plus a specific number of crests. Certain upgrades provide discounts on Flightstones. 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 the two currencies.
Item upgraders can be found at many locations, including the main island, as well as a few outposts. The NPCs offer an upgrade coupon as well as the possibility of obtaining the latest recipe. The upgrade discount increases depending on the amount of items being upgraded. It is also possible to be increased by requiring players to complete specific achievements or quests.
Unlike Cromwell in Baldur's Gate II, there is no upgrader for items available at the start of Icewind Dale. The NPCs that can assist with upgrades are only accessible via a variety of ways. This is both a benefit and a disadvantage.
In Season 3 the upgrade system has been modified a bit, and numerous new features added. Once an upgrade has been completed to a certain item level for an armor slot upgrading other items to the same level will cost less. This applies even if those items come from an entirely different set of equipment.
The amount of Valorstones required for upgrades is decreased, and the discount is account-wide. The amount of Harbinger Crests required for upgrades is reduced too, but it is only available once certain milestones are achieved.
Crests
When upgrading gear in WoW, players have a few choices. They can make use of Flightstones, which are a general upgrade currency that is accessible to everyone players, or crests, which are more specific and consumed during upgrades at specific levels of the item. Crests are an essential part of the Dragonflight gear progression system, which was introduced in 10.1 and are available in four ranks.
The first thing to remember is that the crests can only be purchased for gear of a certain rank. Each rank has an upgrade path that is different. The most basic and straightforward upgrade route costs 15 crests while the most complicated can require as much as 20 crests depending on the kind of gear being upgraded.
Players can earn crests through working through content that is of the appropriate level, whether that means walking around and doing outdoor activities to get lower-tier gear, raids or dungeons with all difficulty for items of higher tier or Mythic+ heroic raid bosses and dungeons for gear that is used in the endgame. These crests can be exchanged with an item upgrader, such as Cuzolth or Vaskarn in Valdrakken for the appropriate upgrade steps and paths.
The new currency system isn't complicated to use, but it will bring some changes to the upgrade process. For instance, when an item is at the highest level of upgrade for any rank (Explorer, Adventurer, Veteran, Champion, Hero, or Mythic), it will no longer require Flightstones to be upgraded. This change allows players to upgrade their equipment to the highest possible ilvl on all their characters rather than relying on seasonal loot.
Another notable modification is that crests have one usage and it's crucial to make use of them in a responsible manner. For instance it's a good idea make use of all your Whelpling-rank crests with the best equipment you have and keep Drake and Wyrm crests for the next batch of upgrades you're planning on making. This is particularly true for items like rings and trinkets that take up multiple slots on the character, which can only be eligible to benefit from the account-wide discount when all of the slots are full of high-quality gear.