In general, I always cling more towards the permanent characters, although there is always an occasional additional character that I might like. I guess I like to engage myself in the social politics of sitcoms a lot of the time so the ones that remain are to have more of an impact on me. For the temporary characters, I get more of a "they're alright, but they're not going to be here next season anyways" impression, lol.
So I guess that's why season 7 and 8 didn't give me a needed aspect in that respect.