My humble opinion (newbie here, perhaps wrong who knows) is that it is impossible to discern the fruit unless you look through the eyes of the Holy Spirit, human discernment is 100% unreliable. I for instance did many seemingly good things in my past that bore no or bad fruit, and my OCD is helping me acquire Christian virtues the hard way, so it's bearing good fruit in my spirit. On the other hand, my struggles and arguments with my husband years ago have turned to our true Christian conversion (and hubby was a darth metal guy!). I could never have predicted the kind of fruit borne from these events. That's why I find it hard to judge, or discern, people. You can never know what they are going through and why, only God. I also believe that sometimes, throughout a single life, you bear good fruit and some others you have become worse than useless and are to be thrown to the fire, purified and transformed and start your life anew. This applied to common people, about prophets I know less.