WoW Upgrades - The Item Upgrader
Upgrades give a guaranteed boost to specific stats. Each upgrade increases item level by +3. A random additional substat is also increased with each upgrade.
Upgraded gear is generally more useful, unless the item has low requirements by nature (like FB sorc shields) or has a large variance in stats (like the eth Titan weapons). The latter see less value from upgrading due to the need to roll to get a perfect version.
Recycle Points
The upgrader for items allows players to upgrade gear to a higher item level by supplying the appropriate currency to the NPC. Upgrades can be applied to any type of armor or weapon. The item used to upgrade the item is discarded and cannot be used again. Upgrades can also be used to create the enchantments.
The upgrader is located in all major cities, and can be accessed anytime to upgrade your equipment. It is recommended to visit the upgrader at least once every few weeks, to ensure that your equipment is up to date.
Upgrades can cost more based on the level of the item but they will always be cheaper than buying new equipment. For instance, upgrading a Benthic chest piece to 385 levels will cost 20 recycle points purchasing a similar piece from another player will cost 105.
Valorstones
Upgrades are items that can be used for weapons, armor, tools and accessory upgrades. They can be bought by players from item upgrader NPCs in exchange for different currencies, and may also be found in random treasure lists. Once purchased, an upgrade is able to be applied to any weapon, tool or armor. The button will show the item's next level of upgrade, if there are enough materials.
The upgrade cost depends on the slot of the item and the current item level and the weapon's price is higher than gloves or bracers for example. Each upgrade cost 15 Flightstones and a number of crests, with some upgrades having a discount to reduce the cost of the Flightstones or crests that are used. Once an item has been upgraded to a certain degree and is degraded, it can be sold and sold back to the upgrader for a lower amount of the two currencies.
Upgraders for items can be found at many locations, including the main island, as well as a few outposts. The NPCs provide an upgrade discount as well as a chance to get a brand new upgrade recipe. The upgrade discount increases as more items are upgraded. It can be increased if players finish certain achievements or quests.
Contrary to Cromwell in Baldur's Gate II is no item upgrader available in the beginning of Icewind Dale. Instead the NPCs that are available to facilitate upgrades must be acquired through several methods that are both an improvement and a drawback.

In Season 3, the upgrade system has been tweaked a bit, with several new features added. Once a player obtains an upgrade to a specific level for an item in an armor slot, upgrading other items to that level will cost less even when they belong to a different gear set.
The amount of Valorstones needed for upgrades is decreased, and the discount is available across all accounts. Similarly, the amount of Harbinger Crests required to upgrade is also reduced and is not available until players achieve certain milestones in their achievement.
Crests
When upgrading gear in WoW players have a couple of choices. They can make use of Flightstones which are a common upgrade currency that is available to everyone players, or crests, which are more specialized and used to upgrade specific levels of items. Crests are a crucial element of the Dragonflight Gear Progression System, which was introduced in version 10.1. They come in four ranks.
The first thing to remember is that crests are only available for gear that is of a particular rank. Each rank has an upgrade path that is different. item upgrading and easiest upgrade is 15 crests. The most complex upgrade can require up to 20 crests, depending on the kind of gear being upgraded.
Players can earn crests by finishing content at the appropriate level, whether that means walking around and doing outdoor activities for gear of lower tiers, raids or dungeons with all difficulty for items of higher tier or Mythic+ dungeons or heroic raid bosses to obtain endgame gear. These crests are then exchanged with an item upgrader, such as Cuzolth or Vaskarn, in Valdrakken for the appropriate upgrade steps and routes.
The new currency system isn't complicated to use, however it does bring some changes to the upgrade process. For example, once 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 is designed to allow players to upgrade their equipment to the highest possible ilvl on all their characters instead of relying only on seasonal loot.
It's also important to use crests with care, since they have only one purpose. It's best to put your Whelpling-rank Crests on the best gear that you can find, and keep Drake and Wyrm Crests for the next round of upgrades. This is particularly true for items like rings and trinkets that fill multiple slots on the character, which will only be able to avail the discount for all accounts when all of the slots are filled with high-quality equipment.