If you periodically prune your neighbors...
If someone hasn't logged in for a while and they don't clear their towns, I keep an eye on how long they're gone for and if it's a week or more I will probably delete them, but it depends on the situa...
Forum Discussion
I generally prune during events, or to make room for forum regulars (pruned 2 neighbors today!). When doing so I look first at last login. If you havent logged in for 3-4 weeks, you are probably done with the game. The next criteria is around design. I don't generally delete any active neighbor, regardless of design aesthetic, but I hate just seeing someone dump all the buildings with no design at all - this signals to me that its a feeder town. I accept that everyone isnt a talented designer, but one of the things I love about the game is being inspired by my neighbors creations.
