BY WHAT standards is a kitchen well-equipped? Must one invest in a collection of tin-lined copper pots, a six-burner Garland stove and drawers full of gadgets? Buy cookbooks by the truckload? The answer is an emphatic no. If there's one thing cooking professionals agree upon it's that acquiring all the items on a checklist of, say 50 or 100, does not make a well-stocked kitchen. Experts stress the need to individualize a kitchen, building up an equipment wardrobe and accessories by picking and choosing gradually according to your style, skill and budget.

The biggest investment in your kitchen probably will be pots and pans. Interested cooks want to buy cookware that performs well and lasts. Does that mean the most expensive cookware? "No," says Calvin McMullen, assistant manager of the Kitchen Bazaar on Connecticut Avenue. "Even if you could afford the best, it doesn't mean you should go and buy copper. The best isn't always the best for every kind of cooking and for everyday use."

Sharon Long, a cooking teacher and manager of Williams-Sonoma at Mazza Gallerie Mall, recommends an assortment of cookware. "People sometimes ask what type of saucepan to get. There's no rule. It depends on the kind of cooking you're doing, how many people you're feeding." No one material is ideal for all cooking. For example, you don't need a heavy copper saucepan to boil an egg, steam vegetables or cook pasta. Heavy weight is important for skillets and saute' pans where high heat is used.

When deciding what kind of cookware to buy, determine what it is made of and consider these major points: even heat distribution, weight, maintenance and utility.

Copper conducts heat efficiently and evenly. It provides quick distribution with low heat and it cools rapidly when removed from the heat source, so it's wonderful for making sauces and toasting seeds or crumbs--where moments of overcooking can make the difference. Copper is beautiful, too, but there are drawbacks.

Copper cookware involves major upkeep and monetary investment. It requires skillful handling and polishing (because copper oxidizes and discolors) and it's not a pot you can abuse.

Because copper reacts with acids (wines, vinegars, tomatoes, lemon juice), pans must be lined. Block tin is used most often and pans must be re-tinned every few years, according to use. (For retinning information, contact the Bethesda Art Metal Works, Inc.)

"I wouldn't recommmend copper for everyday use," says Long. "The pans have to be retinned more often, adding to the expense."

To protect your investment, never place an empty tin-lined pan on the heat because the tin finish will be ruined. (Tin's melting point is 450 degrees, a rather moderate stove-top heat.) Don't use abrasive cleansers or steel wool because they may scratch the tin.

Since there are no easily recognizable brand names and since quality varies dramatically, choosing copper cookware requires careful comparison shopping. Prices differ widely, and copper wares sold in supermarkets, dime stores or hardware stores are often inferior, lightweight pieces better suited for planters or for decorating a wall.

If you're looking for good saucepans, heavy gauge is what you need. For example, better quality saucepans are at least 1/8-inch thick with a tin lining and with cast iron or brass handles riveted on. Some of the newer American-made copper pots (as opposed to imports from France or Portugal) are lined with stainless steel, which is acceptable.

Stores that carry large selections of copper often stock several weights. The heavier weights are more expensive. Lift the pots; get used to how it feels in your hand. Choose a weight that's comfortable to handle.

Both Williams-Sonoma and Bloomingdale's carry copper made in France, either with a smooth finish or hammered exterior. Lids are sold separately, adding to the cost.

The copper at Williams-Sonoma, made by Mauviel, comes in both an extra-heavy professional weight and a medium weight. The heavier weight saucepans range from $88 for a 2-quart pot to $121 for a 4-quart size. A 2-quart saucepan in the lighter weight costs about $65.

Bloomingdale's copper is made by Havard and prices range from $65 to $100 for saucepans. A 3-quart saute' pan costs about $110. Lids are about $12 to $28 extra.

Aluminum is the next best material in conducting heat and probably closest to an all-purpose cookware. It's not as heavy as copper or cast iron and it doesn't have the extra maintenance consideration.

Although raw aluminum reacts with acids and eggs (it's been known to turn custard green), anodized aluminum pans such as Calphalon and All Clad Ltd. by Master Chef -- two of the big sellers -- have solved the problem.

Technically speaking, the aluminum pan is dipped into a chemical solution that is then charged with electric current. The process changes the molecular structure of the pan's surface and creates a specially-fused finish (not coating) that transfers heat evenly, browns well and is easy to clean.

Calphalon is the most widely available cookware of this type. Prices at the area cookware stores are fairly competitive ranging from $16 for a butter warmer to more than $125 for an 8 1/2-quart casserole. A 10-inch omelet pan averages about $34 and a 3-quart saute' pan about $70. All Clad Ltd. pans have an anodized exterior and a stainless steel interior, and are priced higher than Calphalon. At Kitchen Bazaar, for example, a 3-quart saute' pan by Calphalon is $72 and the same size pan in All Clad Ltd. is $105.

China Closet offers a 10 percent discount with the purchase of 3 items in a cookware line.

Bloomingdale's Calphalon and All Clad prices were both markedly higher than the average. The same Calphalon 5-quart saute' pan was $92.50 at Bloomingdale's and $83 at Williams-Sonoma.

Cast iron absorbs heat slowly, evenly and holds it well, making it great for bakeware and skillets. But it's heavy and may prove a maintenance problem. One way to avoid rusting is to season it well or dry it over heat after washing. It can crack if exposed to rapid extremes in temperature (like putting a hot skillet in cold water).

Pre-seasoning maintains the skillet and prevents food from sticking badly. The seasoning is like a hot oil treatment for your cookware. When heated, the metal pores open to take in oil. To treat, fill the pan with oil and heat until oil is very hot, but not smoking. Keep at that level for 15 minutes. Cool and wipe the pan with paper towels. After the pan's been seasoned, don't clean with soap; it can ruin the seasoning. Instead, rub with coarse salt or rinse with hot water and dry over heat.

Enameled cast iron conducts heat well and doesn't have to be seasoned. The enamel coating prevents acid foods and wines from reacting with the metal. It's also attractive and goes from stove to oven to table with ease. It's great for simmering (rice, stews) but not good over high heat, which damages the enamel.

Le Creuset/Cousances brand is carried widely, on sale often and offers a large selection of enameled cast iron. Prices range from about $15 for a 6-inch skillet to about $130 for a 13-quart round oven with lid. A 2-quart saucepan costs about $45. Kitchen Bazaar and Bloomingdale's offer the widest choice of colors and sizes.

Stainless steel is easy to clean and attractive, but is not a good conductor of heat, which is why it needs to be clad with a layer of aluminum or copper on the bottom. It also has a tendency to develop hot spots with age.

A new product line is the Farberware Advantage, which has an aluminum core sandwiched between a stainless steel exterior and interior. Some cookware people say the advantage is mainly the attractive appearance. Prices start at $52 for an 8-inch fry pan or 1-quart saucepan and go up to about $125 for 12-quart sauce pot.

With an idea of cookware properties in mind, think about what size saucepans, stockpot and casseroles would fit your cooking and entertainment needs.

The China Closet's Blanche Sussman says she doesn't like to dictate pan sizes. "It's a personal choice. Just remember: You can always use it if it's a little bit big, but not if it's too small. That's one reason I say never buy sets. You'll always get one slow-selling item the manufacturer wants to get rid of and you probably can live without, such as a 3/4-quart saucepan. Unless you're heating baby food, it's really useless."

A basic list of suggested items would include:

* Assorted saucepans with lids (2-quart, 3-quart and 4-quart sizes).

* Two sizes of skillets with lids and perhaps a 3- to 5-quart saute' pan with lid.

A saute' pan differs from a skillet in shape and depth. Foods to be saute'ed (cooked quickly in fat over high heat) are usually minced or pounded thin and need space to be tossed around. The straight-sided design of a saute' and its depth of about 3 inches makes it a handy piece of equipment, good for cooking chops, scallopini, or large amounts of onion and mushrooms.

* A 14- to 20-quart stock pot (if you make large quantities of stews, soups or stocks).

* A heavyweight dutch oven with cover (5- to 7-quart size).

* A heavy gauge roasting pan with rack (preferably a Teflon-coated rack, which prevents food from sticking).

* Assorted casseroles for roasting, stewing, browning and baking (here the size depends on your needs--large families that eat lots of casseroles need bigger dishes than a single cook who prepares macaroni and cheese for dinner).

But cooking experts reinforce the advice to buy whatever suits your needs. Cooking teacher Sharon Farrington favors her steel wok. "I use it in every cuisine I cook. It's effective, versatile and convenient. Under most conditions it gives a better result than any other pan in my kitchen. I scramble eggs in it, cook paella and deep-fry in it."

That approach is one-pot stocking.