For me to unsub...?

Probably when I feel like I am personally no longer able to get anything out of the game. Which for me is incredibly difficult since I enjoy achievement hunting, whether it has been on this game, or on another platform entirely, e.g., on Playstation before I migrated to PC. Granted, some months I may only play for a few days in the week, and for maybe only 2-3 hours at a time, depending.. and some other months I'll play a significant amount more.