Unfriending Etiquette

There are certain neighbors I won't delete. There are forumites (and former forumites) who have been extremely kind to me, or have just been consistently great neighbors, and I would feel bad about dumping them. There's actually one who I currently cannot visit because his town crashes my game, and I still wouldn't delete him. There's also my BF, who I of course wouldn't delete.

Otherwise it depends on events. If someone regularly disappears, they get a week. If someone disappears during an event, they get a few days, bit longer if they're a forumite. If someone played regularly and then disappears and it's not an event, I'd give them a month.