Talk:Humanity (gameplay mechanic)/@comment-74.106.45.135-20140625080615/@comment-4511886-20140625100432

Item discovery will, as its name suggests, increase the rate for gaining item drops.

Items are dropped from enemies with a set chance. Increasing item discovery will increase these chances. However, it's still based on your actual luck, so it's not worth to bother with figuring out exactly how much you need for a certain percentage chance. Just get as much as you can when you need/want to farm an item.