WoW Upgrades - The Item Upgrader
Upgrades can give you boosts in specific stats. Each upgrade boosts the item level by +3. Each upgrade also increases an unspecified substat.
Upgraded gear generally sees greater value for trade, unless it has inherently low requirements (like the FB shield of the sorc) or very high stat variance (like the eth titan weapons). The latter see less value from upgrading due to the requirement to roll for a perfect model.
Recycle Points
The item upgrader lets players upgrade their gear by offering the currency to an NPC. Upgrades can be made on any kind of weapon or armor. However, the item that is used for the upgrade will be consumed forever and will not be able to be used again. Upgrades can also be used to create enchantments.
The upgrader can be found in all major cities and can be accessed at any time to upgrade your equipment. To ensure that your equipment is up-to-date, it is recommended that you visit the upgrader each couple of weeks.
Upgrades will cost more depending on the level of the item however, they are always cheaper than buying new equipment. Upgrades such as upgrading a Benthic chest up to 385 ilvl will cost you 20 recycle points. A similar item will cost you 105.
Valorstones
Upgrades are items that can be used to upgrade weapons, armor, tools and accessory upgrades. They can be purchased by players from NPCs that sell upgrades to items in exchange for different currencies, and can also be found in random treasure lists. Once item upgrades has been purchased it can be applied to any weapon, tool, or armor with a button, which displays a preview of the item at its next upgrade level in the event that the player has enough materials.
The upgrade cost depends on the slot of the item and the current item level, with weapons costing more than gloves or bracers for instance. Each upgrade cost 15 Flightstones plus a set number of crests. Some upgrades offer a discount on the Flightstones. Once an item is upgraded to a certain amount, it can be downgraded and sold to the upgrader at a lower price.
item upgrades have upgraders for their items in addition to the main island and a few outposts. The NPCs offer both an upgrade discount and the chance to get a brand new upgrade recipe. The discount on upgrades increases depending on the amount of items being upgraded. It is also possible to be boosted by having players complete some specific achievements or complete quests.
Contrary to Cromwell in Baldur's Gate II, there is no upgrader for items available at the beginning of Icewind Dale. Instead the NPCs that are available to help with upgrades must be acquired through a variety of means, which is both an improvement and a drawback.

In Season 3 the upgrade system was tweaked a bit, with several new features added. Once a player has upgraded to a certain item level for an armor slot upgrading other items to the same item level, will cost less. This applies even if the items come from an entirely different set of equipment.
The amount of Valorstones needed for upgrades is reduced, and the discount is available across all accounts. Similarly, the amount of Harbinger Crests required for upgrades is also reduced and is not available until players have reached certain milestones in their achievement.
item upgrading have several options when it comes to upgrading their equipment in WoW. They can choose to use Flightstones which are a common upgrade currency available to everyone players, or crests that are more specific and used to upgrade specific levels of items. Crests are an essential part of the Dragonflight gear progression system introduced in 10.1, and come in 4 ranks.
The first thing to note is that crests are only able to be used on gear of a specific rank, and every rank has different requirements for its upgrade path. The most basic and straightforward upgrade route costs 15 crests while the most complicated can require as much as 20 crests based on the kind of gear that is being upgraded.
Players can earn crests through finishing tasks at the appropriate level. This could be by engaging in outdoor activities or taking on dungeons and raids of all difficulties to get equipment of lower tier or Mythic+ raid bosses or dungeons with a heroic difficulty for endgame gear. These crests can then be exchanged at an upgrader NPC like Cuzolth in Dornogal, or Vaskarn in Valdrakken, for the appropriate upgrade pathways and steps.
The new currency system isn't difficult to use, but it will bring some changes to the upgrade process. For example, once an item is at the highest level of upgrading for any rank (Explorer, Adventurer, Veteran, Champion, Hero, or Mythic), it won't need Flightstones to be upgraded. This is to allow players to upgrade their equipment up to the highest level possible on all their characters, rather than relying solely on seasonal loot.
It's also crucial to choose crests in a wise manner, as they are only used for one purpose. For instance it's best to utilize all of your Whelpling rank crests on the best equipment available and then keep Drake and Wyrm crests for the next batch of upgrades you're planning to create. This is especially true for items like rings and trinkets that fill multiple slots on the character, that will be able to avail the discount for all accounts when all slots are filled with top-quality gear.