Every six weeks or so, a Facebook friend announces (s)he is cleaning up their friend list, and the "weaker" friends are going to get the axe. (I'm using "weaker" in the Granovetter sense of the word here.)
I'd like to suggest this is the wrong approach. Instead, they should axe their closest friends first. If they are relying on Facebook to tell them what's going on in their closest friends' lives, they're not that great of a friend. I'm thinking that the focus should be on richer interactions with the strongest friends, and use Facebook for what it is very good at: a lightweight ways to stay in touch with weak ties. About 18 months ago, there were a few social network services that tried to emphasize the strong ties over the weak. Unfortunately I can't remember their names or where they are now. I'd guess nowhere: social network apps in the Facebook model are just bad at strong ties, compared to something like a text messaging service.
Of course, one of the challenges is that Messenger and such like start to drag you back into the Facebook ecosystem. Perhaps a bug from my point of view, but exactly what Facebook wants.