Go ahead and refine all equipment as much as you can, because, if you change equipment in the slot with a new one, it will keep the refinement level of the previous item. In other words, refinement upgrade is bound to the equipment slot and not directly to an item.
Refinement affects maximum tempering level. Maximum tempering level of an item will rise at refinement level 5 of that item and every 2 levels thereafter (at refinement level 5, 7, 9, 11…). In the game description for this upgrade (every 5 levels) is inaccurate.
Refinement will increase different attributes depending on item type:
-Main Weapon and Side Weapon: Attack and Elemental Attack
-Necklace and Ring: Attack, Elemental Attack and primary resistance type (the highest resistance value for a particular item)
-Helmet, Armor, Gloves, Boots: HP, Defense and primary resistance type (highest resistance value for a particular item)
The best ways to get equipment drawings:
-By using an Auto-Loot option in the Main Campaign (Adventure => Battle Tab). To do this, tap on the item icon, tap forge, refine, equipment drawing icon, after that, tap how to get, and all campaign instances that you’ve finished with 3 stars and have that drawing as possible loot will be available for auto – looting. From what I’ve seen so far, it looks like instances that have main or side weapon drawings as possible loot are usually harder to beat with 3 stars than other instances in the same Chapter.
-Team Instance: Beating this instance will grant you a very large amount of equipment drawings – higher than any other instance.
NOTE: Chapter 7 is bugged, here you’ll gain level 7 drawings instead of level 2 drawings.
Refinement level 1-3 requires:
Refinement level 4-6 requires:
Refinement level 7-9 requires:
Refinement level 10-12 requires: