WoW Upgrades - The Item Upgrader
Upgrades will give you a boost in certain statistics. Each upgrade increases the level of an item by 3. Each upgrade also boosts the random substatus.
The upgraded gear typically has a greater value for trade regardless of whether it has low requirements (like the FB sorc's shield) or has a high stat variation (like the eth titan weapons). The latter are less valuable from upgrading due to the need to roll for a perfect model.

Recycle Points
The item upgrader allows players to upgrade their gear by giving the currency to an NPC. Upgrades can be applied to any type of weapon or armor. However, the item used for the upgrade will be consumed forever and will not be able to be used again. Upgrades can also be applied to the enchantments.
You can upgrade your equipment at any time by visiting the upgrader in any major city. To keep item upgrades is recommended that you visit the upgrader every couple of weeks.
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 chest piece from Benthic to 385 ilvl will cost 20 recycle points purchasing a similar piece from a different player will cost 105.
Valorstones
Upgrades are items that can be used to upgrade tools, armor, weapon and accessory upgrades. They are purchased by players through NPCs that sell upgrades to items in exchange for different currencies, and may also be found in random treasure lists. Once purchased, an upgrade is able to be used on any weapon, tool, or armor. button, which will show an image of the item at the next upgrade level when the player has enough materials.
The cost of upgrading is based on the item slot and the current item level, with weapons costing more than gloves or bracers for instance. Each upgrade costs 15 Flightstones and a few crests, with some upgrades offering discounts to reduce the cost of the Flightstones or crests that are used. Once an item is upgraded to a certain amount, it can be degraded and returned to the upgrader for a lesser amount of the two currency types.
Item upgraders can be found in many places on the main island as well as some outposts. The NPCs offer both an upgrade discount and a chance to acquire a new upgrade recipe. The upgrade discount increases depending on the amount of items being upgraded. It can also be boosted by requiring players to 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, the upgrade system was 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 another set of equipment.
The amount of Valorstones required for upgrades is decreased, and the discount is affixed to all accounts. The amount of Harbinger Crests needed for upgrades is reduced as well, but is only available once certain milestones have been reached.
Crests
When upgrading gear in WoW players have a variety of options. Flightstones are a currency that is available to everyone who wants to upgrade. Crests are more specific and are used for specific level upgrades for items. Crests are the main component of the Dragonflight gear progression system, which was introduced in 10.1, and come in 4 ranks.
The first thing to be aware of is that crests can only be spent on equipment that is of a particular rank, and that every rank has different requirements for upgrading. The simplest and simplest upgrade is 15 crests. The most complex upgrade could require as much as 20 crests, based on the type of gear that is being upgraded.
Players can earn crests through finishing content at the appropriate level, which involves walking around and performing outdoor activities to get lower-tier gear, raids or dungeons with any difficulty for higher-tier items, or Mythic+ heroic raid bosses and dungeons for endgame gear. The crests can later be exchanged at an upgrader NPC, such as Cuzolth in Dornogal or Vaskarn in Valdrakken, for the appropriate upgrade routes and steps.
The new currency system isn't complicated to use, however it will bring some modifications 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 won't require Flightstones to be upgraded. This change lets players upgrade their gear to the highest possible ilvl on all of their characters, instead of relying on seasonal loot.
Another important change is that crests only have one usage therefore it's essential to make use of them in a responsible manner. It is recommended to use your Whelpling-rank Crests on the highest-quality gear you can locate, and keep Drake and Wyrm Crests to be used for the next set of upgrades. This is particularly true for items such as trinkets and rings that fill several slots. The discount on the account will only be applicable if all the slots on the character are filled with high-quality gear.