https://click4r.com/posts/g/18....194610/7-tricks-to-h
What Are Item Upgrades in Genshin Impact? The item upgrades can be added to weapons, armors trinkets, weapons and gathering tools. They provide additional stats, or extra effects. They can be purchased from vendors or traded between players, or as a reward. It's generally recommended to upgrade equipment, especially when it's unique or rare. However, it's possible to upgrade items too much, especially if they have very high requirements for base equipment. Rerolling Genshin Impact offers a few