DEAR MISS MANNERS: My more mature millennial friends (those of us in our late 20s and early 30s) tend to co-host parties as a group for various celebrations: birthdays, engagements, holidays, etc. Generally, prior to this point in our lives, there was an even split amongst the group for the cost of the event.

However, now that some of us have partnered up, there has been a move to a “couples rate” and a “singles rate” for sharing the costs. For example: $300 for a couple and $175 for singles. But many of our single friends have found the additional cost of hosting the party an unfair “tax” or penalty for not being in a committed relationship.

Is there a difference depending on the event? Say, a holiday party simply for the groups’ common and ancillary friends, versus an engagement party for a sorority sister to whom most of the partners are not close?

GENTLE READER: It has not often been Miss Manners’ experience to hear “mature” and “millennial” used in proximity (unless by way of contrast). But since you have done so, she will answer by saying that the obvious solution is also the mature one: Stop charging admission to gatherings, and let each host throw his or her own party. It will spread out the expense -- roughly -- without endangering longstanding friendships over $25.

DEAR MISS MANNERS: I invited our neighbors and longtime friends to dinner, and asked how many would be attending. They have two college-age children, one of whom lives at home, while the other attends college a few hours away.

While we expected up to four attendees, the reply came back “five.” They had invited their son’s girlfriend to come with them. This is a girlfriend, not a fiancee, nor does she live in their home.

Since when is it permissible to invite others to attend a sit-down dinner at someone else’s home? We do not know this girl! If they want us to meet their son’s girlfriend, shouldn’t it be at a get-together at their home?

GENTLE READER: Sympathetic as Miss Manners is to the plight of the hostess whose guests multiply without invitation, she understands your neighbors’ confusion. You did, after all, ask how many people were coming.

It would have been better to ask after the children -- thereby ascertaining their whereabouts -- and then issue a more specific invitation. Failing that, your neighbor should have volunteered who was around and then asked whom you wished to include. The proper way to avoid the unwanted extra guest is to express pleasure at the thought of meeting her, but apologize that it will have to wait for another occasion. This is more convincing if you have not just moments before issued an open-ended invitation.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: You (and others before) have made it clear on how to politely conduct a dinner-table conversation at a party: The rule is to first speak with the person on your left, followed by the person on your right.

But of course, if I speak to “Mr. Left,” and he, too, is speaking with HIS left partner (not me), and so on -- how does this work? Likewise, when I speak to “Miss Right,” she must necessarily ignore me if she is speaking with HER “Miss Right.” I find this does not work very well at all, due to so many swiveling heads, and it’s quite difficult to carry on two different conversations at once!

GENTLE READER: You are quite right. And the thought of everyone whipping around in the same direction, only to be confronted with the backs of heads, is likely to cause not only silence, but whiplash.

The fault, Miss Manners realizes, is in the laudable modern tendency to remove gender as an automatic factor in the interest of fairness. For example, we etiquetteers now instruct people to hold doors open for one another, not just gentlemen for ladies.

But sometimes that is overzealous. In this case, it should have been specified that the traditional rule is that the hostess turns to the person on her right, and the other ladies at the table do the same.

But what (you may ask) if it is a host who is presiding? And if the guests are not distributed around the table in alternating genders? And what if there are other gender factors involved?

You see the problem. So let us restate the rule:

The person giving the dinner turns right, whereupon alternating guests should do the same. Does that help?

DEAR MISS MANNERS: For some reason unknown to me, my daughter-in-law now addresses my son by his surname rather than by his first name. I thought it strange when I heard it for the first time, but did not realize it had become a habit until someone who recently spent time with them commented on it to me.

I think it is disrespectful to my son, but hesitate to say anything to him or to his wife because I do not know if it is my place. I do not want to interfere, but I do want my son addressed with respect. What do you suggest, Miss Manners? Your help is deeply appreciated.

GENTLE READER: It might not be. Nor your help, either, Miss Manners suspects.

How married couples choose to address each other cannot be fathomed by outsiders, even closely related ones. Only they know what is meant to be affectionate and what is not.

Even “darling” may be said in a disrespectful tone. (Miss Manners is thinking of the way the husband in an otherwise happy couple said to his wife, “Sweetie (drawing out the word so that it seemed to have 10 E’s in the middle), that was my king you trumped.”)

So for your own sake, as well as your son’s and daughter-in-law’s, it would be wise to accept the fact that you don’t really know how this was intended.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: We have some relatives who enjoy sharing pictures of their travels. Instead of a slideshow after coming home, they text pictures of themselves or what they’re seeing to a group of a half-dozen relatives throughout the trip.

In the last day, I’ve received 10 pictures, along with all the commentary from everyone else in the group thread. I have to admit that a selfie of them on an airplane and several people responding “Aww!” doesn’t particularly interest me, and disrupts my day.

I’m very happy for them that they are enjoying their vacation, but I’d be happier if they enjoyed it on their own. Is there a polite way to ask them not to send me pictures? I’d be willing to sit through a slideshow once they return; it’s the constant texts that I object to.

GENTLE READER: Perhaps you do not remember the time when it was a common form of torture to make others sit through home movies. Otherwise normal people, with nothing but goodwill in their hearts, would lure their unsuspecting relatives and friends to a purported social gathering, then dim the lights and make them watch films of their holidays and their children’s birthday parties.

There was no escape. Even dozing off in the dark was difficult, because the films were accompanied by equally soporific narrations to which audience responses were sought:

“Here we are in the main square -- honey, do you remember whose statue that is? Help me, someone; he’s one of their national heroes. Anyway, it was festival time, and if it hadn’t been raining you’d be able to see everybody out there celebrating. You really should go there sometime. I forgot -- you have a beach house, don’t you? But you should also travel; there’s nothing like seeing different cultures ...”

Or, “This is so cute: It’s Teddy’s birthday, so of course he thinks the cake is just for him, but Jenny thinks because she’s older, he needs her help to blow out the candles. But the funny thing is that on HER birthday, which we’ll show you next, he thinks it’s OK for him to help her open her presents! And of course she doesn’t like it any better ...”

Surely you do not want that sort of entertainment back. Miss Manners will try to show you that while such barrages of texted pictures annoy you, the method has its advantages:

You don’t have to look at them on the way to the Delete key, because the photographer is not watching you. You don’t have to hit Like, which would hardly be noticeable anyway, among the others on the thread who are admiring one another.

All you have to do is to say, on the travelers’ return, “Seemed like a great trip.” You could have concluded that from the mere volume of the texts, and anyway, no one is going to quiz you on the content.

DEAR MISS MANNERS: I am a church organist. Occasionally, someone will say to me, “You play better than Mr. X.” I consider that a compliment, but to the detriment of Mr. X. How should I respond?

GENTLE READER: ”He’s really very good. I’m flattered that you consider me in the same league.” That this does not address what was said is irrelevant, Miss Manners believes.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)