"If you stand in front of a packed closet every morning and can't figure our what to wear, you don't have a working wardrobe," says Janet Wallach, former fashion merchandising director of Garfinchkel's, author of Working Wardrobe (Acropolis Books, Ltd., $14,95), and a big promoter of the "capsule wardrobe" concept of dressing.

A minimum five-day working wardrobe, she claims, includes 12 pieces: two jackets, three skirts, four blouses, two sweaters and one dress. From these basics, she creates four suits, three dress-and-jacket ensembles, plus several sweater-and-skirt combinations.

Wallach in her book discusses working wardrobes with several women, among them:

Nancy Reagan -- Buys knitted suits with additional parts to extend the usefulness of each item. Her "schematic dressing" is a result of "trial and error and growing up." "If you are in doubt about whether (what you are wearing) is too much," she says, "take it off. Get a three-way mirror and look at yourself from all sides."

Nancy Kissinger -- Limited herself to two dresses and three suits for what was to be a 10-day trip in May, 1974, at the start of her husband (then Secretary of State) Henry Kissenger's "shuttle diplomacy." The trip lasted 30 days, and she was "ready to burn those outfits when I got home."

Kissinger has set guidelines for her dressing when they visit foreign countries. "You are representing the female portion of the United States. You should look like a Westerner," he advised her once when she wanted to wear trousers to an official dinner in China. "How would it look if I suddenly appeared in a pajama suit? You'd think I'd gone crazy."

Diane Sawyer -- Maintains that what may work in the real world may not work on the television screen. The CBS correspondent extends her wardrobe capsule with accessories, the simpler the better, or "the viewer spends the whole time trying to figure out what on earth that says on your pin."

To cover the 1980 George Bush campaign, she lived out of hanging bag holding three jackets, skirts and shirts, from which she plotted three of four outfits. Just changing earring color, she says, makes things look different. She also carried a bright silk shirt and pants. "I can't tell you what it did for me psychologically. When you've lived in sturdy clothes all day long, it's fantastic to put on something flamboyant."