Path of Exile Item Upgrades
The performance of many Path of Exile items can be enhanced by upgrading the performance of them. They can also provide additional damage, AD or even affixes.
Often times however upgraded Common and Magic gear is beaten out by Rare-grade gear due to their requirements.
Armor
Armor upgrades are a type of upgrade that can be used on weapon and armor items. They increase the effectiveness of the item they're connected to. Armor upgrades are found in the world of the game and can be purchased from Blacksmiths at any bonfire. Alternately, they can be salvaged from items that have upgrade components within them by with a professional or higher salvage kit.
The level of an armor's or weapon's upgrade determines the amount of damage it can absorb. The ability to absorb damage of a piece armor will increase as it is upgraded to the highest upgrade level. It's important to remember that this will increase the weight of the armor, therefore it must be heavier.

There are a few different kinds of armor upgrades that are that are available in the game and they all have distinct effects. Certain upgrades grant armor an additional amount of health points while others make it lighter and more powerful. The type of armor upgrade that an item can get is indicated by the name of the upgrade, as shown in the table below.
Certain upgrades require magic or a hybrid technology and magic, which is identified by the "Magic" and "Hybrids" entries in the table below. Certain upgrades require charges for use. They are referred to as "Charges" entries in the table. The charges associated with these upgrades change daily or never expire, depending on the upgrade.
The cheapest method of upgrading armor is with Iron Ore, which can be obtained by exploring the environment and looting small loot chests. Titanium is more expensive however it is obtainable through smelters in Orgrimmar and Stormwind City. Some upgrades, like the Reforge or the Hot Potato Books can only be used on armor pieces of the highest level. These upgrades can provide significant increases in stats and are well worth the cost.
Upgrading a piece of armor to its maximum upgrade level will significantly increase its defense capabilities but the wearer must be aware that putting more weight on it will dramatically reduce its speed and agility. Therefore, it is not recommended to upgrade armor pieces above +9, since the defensive boost gained is usually not worth the additional weight and power costs of the upgrades required.
Weapons
Weapon upgrades allow players to increase the effectiveness of certain aspects of the weapon. Upgrades can increase the accuracy of a rifle or the damage that shotgun shells do. Certain weapons come with special upgrades to improve their inherent characteristics. These include Frictionless Materials (improves stability and decreases the chance of weapon overheating) and Kinetic Coils (increases projectile acceleration for more damage).
Most upgrades for weapons require three Power Dices, a different amount of Minerals and Erons, and a whetblade to apply. These are obtained through either completing Side Quests, killing a certain amount of bosses or monsters, or through the Weapon Upgrade NPC located in Central Flarine.
To upgrade a weapon, equipment set piece, or Whetblade you need to visit the NPC [Armor] Boboko located in Central Flarine, and pay her an upgrade fee of a specific amount of bars. The more bars needed to complete an upgrade the more expensive the upgrade. The cost of upgrading will be lower if have more than one of the upgrade materials.
In Chapter 2: Season 5, the method of upgrading your equipment and weapon sets changed a little. Prior to Chapter 2 Season 5 you could upgrade your weapon and equipment by paying a certain amount of Bars. You could do this until your weapon or equipment reached its maximum upgrade level at which point the upgrades would reset.
You can still do this, however, the process is high on RNG and low on agency. It is better to purchase gear that has low levels of upgrade and high base scores and stat distributions. These items have a higher chance of giving you the most prestigious tier of blessings and perks.
The majority of players will prioritize weapon upgrades for the weapons they most often use to allow them to progress faster. In addition, players should consider upgrading the weapons that are most popular with their squadmates to increase their power as well. Shepard, for example, should upgrade the M92F to unlock the Beretta M93R. This will make the weapon more effective when used by biotic specialists like Grunt and Tali.
Jewels
Jewels can be used to improve the stats of a character or to provide additional effects on weapons and armor. Jewelry crafting is a method of making them, in which you combine gemstones with specific reagents on a jewelry table. The higher the level of the jewel the better the secondary effect. These reagents can be obtained around the world from Treasure Goblins, World Bosses and, sometimes, by salvaging Legendary equipment. You can also buy them from The Jeweler in exchange for Scattered Prisms and gold.
The Jeweler can boost the quality of a gem in stages ranging from Crude up to Royal. Depending on the tier of the gem it will give different stat boosts when it is inserted into weapons, gear and jewelry.
The Jeweler is able to create all kinds of gems, apart from the rare and legendary ones which you must attain an appropriate level to obtain. In contrast to other upgrade components, jewels can be swapped with a jewel of the same type without damaging it. However, you can only replace one jewel in a piece of equipment once.
item upgrades Casesgg is common to use more jewelry for aesthetic reasons. Jewels also enhance performance and create an outer layer that is more durable than metal so that repeated friction from pivots do not damage them.
In addition to the upgrades mentioned above players can also get glyphs for their shields and weapons from a Glyphmaster. These glyphs provide a small boost in power and can be swapped, but they are not guaranteed to be available as loot. Glyphs, like jewelry, can be upgraded at the Jeweler in exchange for Scattered Crystals and gold. Glyphs can also be removed and returned to the inventory. Other upgrade components like traits or aegis can't be exchanged and can only be recovered by using an Upgrade extractor, or salvaging with Black Lion Salvage Kit or an Ascended Salvage.
Trinkets
Trinkets are a great way to give your character many small, but valuable advantages. They are available in the start-up area as loot or personal story rewards. They are also available through vendors and after the completion of road interactions. They can be found on the Trading Post, or crafted by jewelers.
The first trinket a player will be able to unlock is the cloak. It grants a small but beneficial boost in speed of movement and the ability to evade. After that, they can acquire rings, amulets, and necklaces in the same way to how a player can acquire weapons and armor. Each piece of equipment has one upgrade slot that accepts either a universal or a jewel upgrade. Universal upgrades are smaller and can be utilized on any piece of equipment. Jewels cannot be upgraded or replaced and are only compatible with certain trinkets.
These trinkets can also grant bonuses and abilities that are active whenever the hero is not fighting. This enables the hero to perform better when they are not active and may also help fill in the void of a solid team or any slots from the talent tree that normally are filled with the hero's best stats.
A good rule of thumb for trinket upgrades is to prioritize BiS (Best-in-Slot) items that you won't be replacing in the near future, then any items with desirable stats, but less important than the iLevel of the item being upgraded. This is true especially if you are looking to upgrade multiple statistics on an item. It's best to upgrade just one crucial stat rather than two suboptimal ones.
At the beginning of the game players in the jungle are likely to upgrade their trinket to a red, while top and mid players usually choose the pink or green ward (depending on the game's matchup). These choices will have an impact on the hero's ability to manage the map.
In addition to the items mentioned above, players can also find other trinkets in the game in the form of trophies and awards. These can be earned through completing certain milestones within the story. For example, completing the main quest of a chapter or beating the boss. You can see them by clicking on the achievement in the reward section of the hero's menu.