FROM HER vast experience of the world, Miss Manners offers you a single tip that will save you endless amounts of money, trouble and tedium when planning your summer holiday. It is that whatever you do, the social use of it upon your return will be so minimal as to make it quite the same as if had confined your exertions to whatever you felt like and could afford.

There is, Miss Manners admits, some social gain to be had beforehand from grandiose vacation plans. The person who announces plans to go exploring on the moon has it all over the one who voices a preference for staying home to catch up on the yard work and house repairs. Children like to have plans to announce to their classes at the end of the school year, even if they have to pin their hopes of travel on encouraging their parents to divorce and move away.

But pre-holiday arrangements are naturally understood to be subject to last-minute cancellation. You might well have planned to cruise around the world, as you said, but then have realized that you could achieve the same effect by overeating at home and seeing two old movies a day in the neighborhood, without having to be seasick, besides.

It is in the fall, when friends reunite after having scattered, that the recounting of adventures, anecdotes, observations and experiences will count for nothing whatsoever.

Suppose you have seen some of the world's great wonders, and have honed your original impressions of them until you are prepared to describe them in poetic terms that will enable your listeners to share your awe. The best of friends will cheerfully assure you that the very idea of being in such touristy places fills them with horrors.

Perhaps you have spent the time in a remote place, and you are willing to share your discovery and enlarge their vision. They have heard that the plumbing there is dreadful. If you really got to know the people -- the real people, as we say -- of a different land, you may be sure there was a national magazine article recently explaining their collective psyche, which turns out to run contrary to whatever telling characteristic you have derived from revealing encounters.

If you have seen every possible point of interest in a given place, the same friends who have invited you to "tell us about your trip" will go into reeling boredom before you can enumerate what you saw. But if you missed one picture in one wing of one museum in one of the great capitals of the world, they will assure you that it alone is what makes going there worthwhile.

Did you bring back rare and precious objects? Your local department store is featuring a foreign festival where these are available in six colors at two-thirds the price. Did you take care to photograph everything of interest? The only possible way to get anyone to look at them is to offer to look at their pictures, and what a trial that is.

You may feel, after a summer of expensive exertion, that your acquaintance is composed entirely of selfish, frivolous people, only interested in bragging of their own adventures, and unwilling to learn anything from the experiences of others.

Not at all. They are only acting in your interest, showing you that they accept you just as fully for having spent a holiday doing nothing whatever but what you felt pleased to do for its own sake. MISS MANNERS RESPONDS

Q. A am curious as to the rules of summer dress. I have good, well-tanned legs, and in hot weather I prefer not to wear hosiery. After I attended a wedding last year without hose (I was wearing sandals), my mother gave me a lecture as though I were a small child. I cannot understand why, as I keep my legs clean and neat, I was comfortable, and those of us who were not wearing nylons were much more congenial than those who were sweltering in them. I also find it hard to believe that with the wedding itself going on, anyone paid that much attention to my feet.

I have just returned from college, and my mother again has objected to my wardrobe's orientation to bare legs. What should I do?

A. The rule about summer dress for ladies' legs is that you may go without stockings if you don't get caught. While you are correct in saying that the chances of your being noticed at a wedding were small, the fact remains that you did get caught, didn't you?

Miss Manners is, in principle, opposed to increasing informality of dress and quite oblivious to arguments about comfort. Nevertheless, even she has noticed how hot it can get.

She is prepared to offer you a deal. If you will wear stockings to formal occasions, she will persuade your mother not to inspect your feet every time you leave the house. The only formal summer occasions are weddings and funerals. The Fourth of July is definitely informal, and dances don't count because neither your mother nor Miss Manners can tell what you are wearing under a long dress.

Q. Two weeks ago, my escort and I invited another couple for a casual dinner. The food preparation was completed except for the last-minute touches before the arrival of our guests.

The problem: Even though we were in our designer jeans and the occasion had been announced as "casual," the female of the other couple reacted as though I were improperly serving a seven-course meal.

For example, all of us were relaxing with our before-dinner drinks, and we had waited the prescribed 20 minutes after our guests arrived before serving dinner. But when the guests were asked if they were ready to move into the dining room to eat, they smirked and made no reply, which led me to believe that they were not ready to eat. After dinner, they responded in the same manner to our offer of dessert, which, I might add, was an expensive ice cream.

It is my impression that etiquette was first instituted as a way of making guests feel comfortable. How should the hosts respond when guests make them feel uncomfortable or inadequate?

A. It is Miss Manners' impression that the expressions you interpreted as smirks were the visible signs of discomfort produced in your guests by your application of etiquette.

In the silly question sweepstakes, "Are you ready for dinner?" and "Do you want dessert?" rank right behind "Is it all right if I kiss you?" In all cases, the answer is "Of course -- what do you think I'm hanging around waiting for?" But in all cases, it is embarrassing to the person addressed to have to say so. It is bad enough to know that one's eagerness is probably making one look like a zoo animal hoping to encourage the throwing of peanuts, but to be forced to acknowledge this in words is more than most people can bear.

Treats, including carefully prepared dinners, expensive ice cream and big old kisses, should be freely given, not dangled in front of people who are then told the condition is that they must sit up and beg.

Q. I occasionally have dinner in a Middle Eastern restaurant in which entertainment is provided by well-endowed belly dancers who practice their ancient art among the customers' tables rather than on a stage. When a belly dancer approaches quite close to me, is it considered proper form to focus my eyes: (a) on her face, (b) on whatever happens to be at eye level, (c) on the most rapidly moving portions of her anatomy, (d) on the wallpaper design at the opposite side of the room?

A. God has given all belly dancers obvious focal points, clearly marked on the talented parts of their anatomy. If you have never observed this interesting fact of nature, Miss Manners must congratulate you on knowing a restaurant that has such interesting wallpaper.

Q. My husband is a chain smoker with, unfortunately, little regard for the non-smoker. Recently, while having dinner out, he prepared to "light up" when he finished his meal. When I remarked that it wasn't proper to smoke while the others at our table were still eating, he said there was no such rule in any etiquette book. This may be the case, but shouldn't good manners dictate at least the question, "Mind if I smoke?"

A. There is such a rule, and asking if anyone minds is the softest version of it. The stronger version is that smokers may smoke only in the smoking room. If you do not have such a room, the outdoor equivalent is a place known as "behind the barn." The look a dear Edwardian dowager might have given to someone who violated the rule and smoked without regard for the feelings of non-smokers was nothing compared with the reaction one might expect today from some of our more violent nonsmokers.