I dont remember the exact words but at the end of the story when Bilbo bids goodbye to everyone, he tells them something to the extent of that they are all welcome to visit and that teatime is at 4.
In the books they say many of his dwarf, elf, human, and even wizard friends come by the Shire now and then to see him where they enjoy Bilbo’s hospitality and sit up late around the fire talking about adventures.
Have you ever known a person to have such a policy where a person lets others know he is always open for visitors and where they get plenty of them?
In ye olde days (e.g. 18th or 19th century), it was pretty standard for a wealthy person to have regular visiting hours or to host a salon night on a regular basis. Maybe there are fewer idle rich aristocrats nowadays, not to mention that the invention of the telephone removed some of the need for posting visiting hours in advance.
When I was in my 20’s I may have had a modern version of salon.
I referred to it as a professional living room. The details are too numerous and boring to recount, but my living room was always full of people, and “visiting” was known to start 20 mins after my shift at the day job was over, every evening.
Notice that the very first scene in The Hobbit is the preparations for a huge party at Bilbo’s place.
If you already have the reputation as someone who has many and frequent visitors, and it’s well known that you and your guests truly enjoy each other’s company, then sure. But if you were never really big on visitors anyway, I don’t expect they would just magically start arriving.
Before telephones it was difficult to make an arrangement to visit someone. Usually you just had to go round to their house and knock on the door, and hope that they were at home and available.
Hence the convention in households with servants (which was everyone above the lowest class) that the servant who opened the door would say, “I’ll see if he/she is at home.” If the visitor was unwelcome he would be told that, “The master/mistress is out.”
Everyone understood that this was simply a polite convention. But, on the other hand, the person you came to visit might really be out, so there was always some ambiguity, and rudeness was avoided. You could always leave a note, or your ‘card’.
I spent most of my adult life having my home open to anyone who wanted to come by and hang out. It was nice to get a call or text ahead of time, just to make sure that I was home, but it was their loss of convenience, not mine, if I wasn’t able to see a visitor at the time they showed.
I’m home a whole lot less these days, and don’t have roommates to “keep the hearth warm” as it were, so I have many fewer drop by guests, and that, I see as a loss.
I still have a few friends that have a key to the place, and I am quite happy to see their cars in front of my home as I arrive.
I knew a couple of people in my younger days who absolutely trashed their apartments or houses by being the place where people could come and hang out any time.
For me, it was the other way around. Since I was always expecting guests, my house was always pretty well put together. Not saying it was immaculate or anything, but there was no overflowing trash or dishes in the sink. I vacuumed pretty much daily, and scrubbed carpets more than once a month.
Now that there are much fewer guests, I’ve certainly let things go a bit.
For a brief time I shared and apartment with 3 friends. Our place was the place to come and hang out and make plans for whatever groups were doing. Most people brought stuff (mostly beer or liquor or soda & chips) and it was a lot of fun. Only 6 months for me and then I moved back to the ship for my last 6 months in service. I knew half of it was going to be at sea.
The guy who took my spot was another friend and they kept the open apartment concept going for about 2 year after I was out of there with a constant change over in people.
It worked well, but probably helped that most of the frequent guests didn’t have a place to be other than the ship, so they were good guests.
It wasn’t just aristocrats in the past. Middle-class people with time, money and servants would have regular “at home” times for their friends, and there was a whole etiquette about newcomers to local “society” leaving cards to introduce themselves and getting into that sort of circle.
And academics at collegiate universities like Oxford, as Tolkien was, would do likewise, and probably still do.