I have villagers I like and don't like, and try to have at least one of each personality, but I don't really have villagers I "must" have or a final idea of who I want on the island.
I'm thinking of keeping villagers until I get their photo (unless I *really* don't like them), then bumping them out within a few weeks or so with amiibo if they don't move out naturally. What are your plans for moving villagers in/out if you don't have specific ones in mind?
I've decided to let them go if they ping. Ideally after they give me their picture. In practice, we'll see. I love Muffy so much it'd be hard to say goodbye. But I also loved Snooty and let her go when she pinged.