It took me 3 yrs to develop partial trust with one of my F2s. He's 6 yrs old and I get to pet him but I've accepted that we have reached the apex of our relationship. I can't pick him up. If he ever becomes seriously ill, needs to be hand medicated, continues his resistance to being held, he's a goner. That is a difficult prospect for me but it is the nature of the beast. In the meantime, he is content with his life and that makes me happy.