So by far this is a very complicated question when I get something worth considering. Should I spend all my resources on the current finding only to find a better version in next month? There are three variables for every useful perk: its percentage, combination with other perks and its place (first, second, third...). For example, I got a very useful perk with the maximum percentage, but it was third in the list combined with four useless abilities, so I decided to sell it. But I don't have enough information to decide if it was a good decision. Obviously, I'll never get an artifact with five useful stats (except for the money), but what is the level, from which we may concider an artifact to be rare and worth upgrading? Three useful perks with maximum percentage? Or maybe this option is also impossible? What are your boundaries to decide if the artifact worth upgrading?