I used to have all of the slots filled up from friends and anime cons, but after I restarted my town about a year back I've only gotten a few from strangers at the mall/other random places
I had all my slots filled up before, but then when i "lost" my game cartridge and got another i now only have like, 5 or so lol.
Oh but I also clean them out a bit. I delete houses I think are plain or have nothing in them bc for the rare moments i do even decide to go to the HHA park, I want it to be enjoyable
I think I have 5 or 6 from people I've streetpassed miraculously here. It's very rare to get any at all and if I do it's usually a Pokemon player, although I have come across a few Fantasy Life players which is awesome because I'm still slowly playing that game :'D but yeah I had a lot more in my old town when I lived in the states, but that town has since been reset. It was pretty much filled up.
Mine is almost full. There is a McDonalds near my house that is a nintendo zone and lots of people go there to get street passes. I street pass with people who have ACNL pretty often when I go.
My 3DS "consoles" never leave the house and wi-fi is only turned on when I need my villages to swap something. When I need something to kill time, like waiting for an appointment, I carry my Kindle.
I think like 6 houses, they're small houses except one that was big.. but it was empty (and it was my most recent!.. two years ago now)
When I take my 2DS with me the only streetpasses I get are for Pok?mon or Mario Kart and sometimes for Tomodachi life or no games at all, just new miis in my plaza.
That's about the same for me. I would take my DS with me EVERYWHERE, and I have Nintendo houses an one from a friend, and that's it. I wish they made it so that when you have online visitors in your town, you'd get a street/spot pass from them.