When was the last time you talked to these NPCs?

[Rosch]

didnt see harvey on this list but i talked to him a month ago when i wanted to design a room and he just stopped me to tell me about the wedding event. i like harvey tho i should go say hi more

Thanks. Added Harvey into the list.
Only goes to show that I forgot about him because I barely talked to him.

 

[Klauser_Bateson]

Tom Nook: I would say about late May-early June. I decided to do a multi-level library/museum area after seeing a post on Reddit and had to move the Museum out of the way.

Nooklings: yesterday, sold some items I had in my storage.

Isabelle: around the beginning of this month, decided to change my island tune.

Dodos: yesterday, to open my gates. I wanted to give an island tour to a friend of mine.

Mabel: if going into the fitting room counts, then a few weeks ago while I was looking for gifts for Curt and Apollo. If not, then I'm not sure.

Sable: I believe it was either December 2020 or January 2021. Once I got all the patterns, I pretty much stopped talking to her.

Blathers: Yesterday, I donated some bugs and fish I caught.

Redd: It's been a couple of weeks.

Celeste: It's been at least a month, maybe 2. If she happens to be in plain sight then I'll talk to her, but I don't go out of my way to search for her.

Flick/CJ: I'm lumping them together because I pretty much ignored them about a month after the game had been out. I don't care for their models, and I mostly skip the Fishing Tourney and Bug-Off. I also prefer to make bells the fast way with turnips, so I have no use for them in that regard either. Also, CJ annoys the heck out of me in this game for some reason. This might be an unpopular opinion, but I find him a lot more tolerable in Pocket Camp.

Saharah: Two weeks ago, I wanted to see what her mysterious wallpaper and flooring was. I ended up using both in my alt character's house.

Label: About a month ago.

Kicks: Can't remember to be honest, I think it was February or March 2021.

Pascal: A few days ago, he gave me a useless dress. Should've kept the scallop.

Gulliver: I don't wake him as much anymore but I decided to when he showed up last week. And then I couldn't get the black dots to appear on my beach whatsoever.

Gullivarrr: A couple days ago. I'm more inclined to wake Gullivarrr because I'm more interested in collecting the pirate items, mostly the clothing.

Wisp: Sometime last year.

Luna: Never talked to her. I kinda forgot she was in this game to be honest.

Leif: Last week, I bought bushes.

KK: Haven't really paid attention to him since getting K.K. Birthday last month. It was the only song I didn't have since starting a new island.

Daisy Mae: February 2021.

Harvey: Around Mid-June during the Wedding event.