It will feel complete when all Head/Target/Power -masters have been remade. I prefer that phase of G1 over the first few years. I wouldn't mind if they were all done as Titan Masters either. (Referring to the title of the merged threat calling it the "Endgame.") Interpreting the question another way, The endgame for some portions of my collection will be when I sell those I no longer feel the need to keep.