When to drop non-playing friends?
I'll drop when they have nothing to tap. Usually that's about four weeks. I'll keep some long time neighbors that only play for events and I know will come back.
Forum Discussion
I look at inactivity and lack of progress in the game. Right about now I'm starting to look at those who still have not started the clash of clones event. In a couple weeks, if they still haven't started or moved level, but show activity, I will assume they are playing a different origin game and delete them from my friend list. I usually lose a couple friends this way during a big event. For just activity, I go four to six weeks usually.
