Dear Abby: From time to time, you mention the importance of bikers wearing safety helmets, which prompts me to write to you regarding horseback riding.

According to the National Electronic Injury Surveillance System, each year more than 42,000 people are sent to hospital emergency rooms due to riding-related accidents. The American Riding Instructors Association sponsors a certification program. Instructors certified by this program are required to use approved safety headgear for their students and themselves.Since this program was instituted in 1984, we have received a number of letters from individuals who, thanks to the fact they were wearing protective headgear, received non-catastrophic injuries. (In one instance, the rider's doctor told her that the helmet saved her life.)

Few people realize that head injuries are cumulative; several seemingly "minor" bumps and bangs can result in serious problems. Your readers should be aware that appropriate safety headgear is vital in any activity in which the head is readily exposed to injury. Those who say they can't afford a helmet should check out the cost of brain surgery!

- Charlotte Brailey Kneeland, ARIA Certification Program, Alton Bay, N.H.

Dear Charlotte: Since most people might associate riding accidents with bicycling or motor-cycling, your letter provides a helpful reminder of the fact that horseback riding, too, contributes its share of head injuries.

Many enthusiasts insist that "to wear or not to wear" should be a matter of personal choice. However, it should be remembered that organ banks report that the best candidates for organ donations are hospital patients on life support, with nonreversible head injuries.

Dear Abby: I enjoyed all those letters about zippers. Here's another one:

A gentleman was dining alone at a Beverly Hills restaurant, unaware that his fly was unzipped.

His waitress noticed this, and very discreetly handed him a piece of paper on which she had written:

"Dear Sir: I notice that your fly is unzipped and wide open. I will go to the other end of the room and drop a tray full of silverware on the floor to attract everyone's attention to that area while you zip up your fly."

- Longtime Reader in Beverly Hills, Calif.

Dear Longtime: I hope he gave that waitress a nice tip for the tip-off.

Dear Abby: I just read the letter from the retired couple on a fixed income and who had very little to spend for Christmas gifts.

My husband's grandparents are also on a limited budget, but every year, we get a wonderful homemade gift from them. The great-grandchildren get handmade ornaments and paperback books.

One year, Grandma bought some cookie tins and filled them with the most delicious homemade fudge, and she taped the recipe on the lid!

Now, I, too, can make the world's best fudge!

- Maleah Smitham

Dear Maleah: If it's not a secret, please send me the recipe.

Good advice for everyone - teens to senior citizens - is in "The Anger in All of Us and How to Deal With It." To order, send a business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Anger Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)