While retail businesses nearly everywhere are floundering, some District secondhand and thrift stores are enjoying a surge of business.

A growing throng of well-to-do and poor customers is finding that some stores that once had the dingy appearance of a basement warehouse are expanding and taking on the appearance of full-fledged department stores.

Shopping at thrift stores has become part of the normal buying pattern for consumers in general, and lately, for the more affluent shopper in particular, according to Fannie Gladden, manager of Amvets Thrift Store at 6101 Georgia Ave. NW.

"Doctor's wives, lawyers, and businessmen patronize our store," said Gladden. "A man can pick up a used Garfinckel's suit here for $20 and a designer shirt for $3. They realize that it doesn't make sense to go downtown and pay inflated prices for the same items."

"You find that the people who used to park their fancy cars around the corner and walk a block to the store are now pulling up to the front door," she said.

Marvin Hartz, who was examining trousers in the Amvets store one day last week, said he shops there "because of the bargains and the quality of the merchandise. There's no guarantee, but you can look at the things and see how good they are. If you go to a regular store you have to pay more and the clothes are not as sturdy as the clothes in the thrift store."

Molly Haines, public relations person for Goodwill Industries, said "the profile of the person who shops at our store has changed dramatically.

"You find Middle Americans, the Sears shoppers, are buying at our stores. You find the affluent shopper here. We have had to physically separate the cream of our donations into a boutique within the store," Haines said.

The Amvets store's proceeds are used to benefit veterans, while Goodwill profits benefit handicapped persons. The Salvation Army's thrift store at 451 First St. NW helps to support its alcohol rehabilitation program. All three operations depend on donations of goods.

Gladden said donations from middle-income families have decreased over the past year, but the stream of articles coming from the more well-to-do has remained steady.

The brightly lit aisles of Amvets resemble those in a discount department store rather than the image of musty, dark disarray traditionally associated with thrift stores. Items ranging from fur coats to kitchen utensils are arranged in orderly displays by department.

"We have a large volume of merchandise coming through here, so we must have as quick a turnover as possible," Gladden said. "The markdown is determined by how long the item is in the store."

Mary Taylor, who has been sorting through secondhand items for the Salvation Army for the last 20 years, said hers is "a never-ending job; we never get done. We have mountains of articles: silver, crystal, antique trains and dolls. We could have a Rembrandt come through here and never know it."

Although the volume of donations to the Salvation Army "has been like this for years," Taylor said, this time of year it becomes especially heavy because "people get especially freehearted during Christmas and tax-write-off time, and we find ourselves getting even more backed up."

At the Salvation Army warehouse at 526 First St. NW, near the thrift store, an early weekday morning finds a crowd of shoppers bartering for furniture that needs refinishing or minor repairs.

"This place has been like this every morning for years, it's crazy. But now you find everybody in here looking for a bargain," said warehouse manager Bill Linebaugh.

Haines said that because goods produced today generally are of lower quality, people are coming to the Goodwill store at 2200 South Dakota Ave. NE in search of better constructed articles built years ago.

"Years ago, Goodwill was a store where poor people shopped. People thought of thrift stores as dirty places where you rummaged around for cheaper things because you had very little money. Now, with the kind of shape the world is in, people can ill afford not to shop at thrift stores," she said.

Unlike the Goodwill, Amvets and Salvation Army thrift stores, Classic Clothing is a commercial enterprise. The company, with stores in Georgetown and in Northeast, has witnessed a burst of new business and a change in clientele similar to that of the charitable organizations, however.

Charlotte Streidel, whose family has owned Classic Clothing for four generations, runs the business with the help of her husband and three sons.

The eldest son, Brian Streidel, who manages the boutique at 1015 Wisconsin Ave. NW in Georgetown, said, "business is up 35 percent from last year. This is a place for people who want to be stylish but can't afford to buy new clothes. In this store we provide a nice atmosphere and the clothes are sized and in order. This is for a person who wants a bargain but is willing to spend a little more in order to escape the work involved with searching out a garment in our other store."

The Classic Clothing store at 3701 Benning Road NE has 10,000 square feet of crates upon crates of garments. "I have seen people spend hours going through these crates," said Charlotte Streidel. ". . . People who have to look nice every day, like embassy people and government workers, do their shopping here." Her explanation: The quality of fabric and workmanship in the old clothes cannot be duplicated today because of the cost involved. "Today's manufacturers simply cannot afford to make the clothes we sell."

Classic Clothing customer Crystal Rivers, a receptionist who shops at many area thrift stores, explained her habit simply: "The turnabout in fashion and the quality of the merchandise are the reasons why I like thrift shopping, plus it's fun."