Carol Watson has worked at the installation thrift shop for 20 years. Tomorrow marks the anniversary. The wife of a former command sergeant major for the Old Guard, Watson runs the cash register in the main store. But saying she rings up totals and writes out receipts would be greatly understating her responsibilities.

‘‘Carol is usually the first person customers see when they come inside. She serves as the official greeter,” said Jeane Moore, thrift shop manager. ‘‘She’s always willing to pitch in wherever help is needed. She’s very special ... a 14-carat gold person. She has this endearing attitude of welcoming and assisting people. She’s provided years of service, dedication and kindness.”

‘‘Carol is an institution here,” said Anne Anderson, the thrift shop’s bookkeeper. ‘‘She remembers so much about people.” Anderson said Watson knows what customers are looking for when they come into the store and she’ll alert them to newly acquired merchandise on their visits.

Customer Kaye Oman said Watson keeps an eye out for newly arrived baby clothing that comes into the store, knowing the woman collects it for a children’s charity.

‘‘She’s very friendly, kind and supportive,” said Oman. She’s interested in you — not just what you’re buying.”

‘‘She keeps an eye out for things she knows you’ll like,” said Cecilia Erts, another regular customer. ‘‘She doesn’t try to push things just to sell them. She never gets fussy. She treats everyone the same. She’s friendly and without pretense. She makes the place different because she’s very warm.”

‘‘She’s just very open to people,” said Kathy Candido, thrift shop board chairman.

The register can be tricky duty, other volunteers say, particularly when lines form and customers get agitated. Carol never gets flustered with the ‘hustle and bustle when it’s overcrowded,” said Candido. ‘‘She’s got a great sense of humor and jokes with customers. She makes light of things knowing that tomorrow is another day.”

And if you think the Fort Myer Thrift Shop is just a sleepy little boutique, think again. Moore said the last two Saturdays the store was open it sold $15,000 an hour in merchandise. That’s a lot of volume, she said, especially when you consider the bulk of items the store sells are priced at 25 cents to $4. More said the biggest sellers are furniture and clothing in the main store, Bldg. 224, and jewelry, crystal and knick-knacks which are sold in an adjacent specialty store, Bldg. 225.

It’s not just Watson’s spirit that inspires people. Moore said she’s a ‘‘fabulous Southern cook” and is responsible for maintaining the flowers that grow in front of the shop.

‘‘She’s a good gardener,” affirmed Euts. ‘‘Without her there wouldn’t be any plants outside.”

Moore said Watson used to bring hotdogs for her fellow staffers when she worked her Saturday shifts. Sometimes its soup, more recently she’s been bringing cider and cookies that are given gratis to customers.

Watson, caught on duty at the thrift shop Tuesday afternoon, seemed a little embarrassed by all the hoopla. She said she’s done what she’s done for so long ‘‘because of the people, the customers and coworkers — they’ve all been good to me.”

If you watch Watson work you can observe her easy way with customers. She jests with them and looks out for their interests when they make purchases. Rolling a rounded Christmas ornament between her hands, she points out a worn spot where paint has come off. ‘‘You still want it,” she asks the customer, who nods her head, thankful for the thoughtfulness.

Watson said she puts out home-baked cookies and cider ‘‘to show her appreciation for the customers.” Besides, she said, she loves to cook.

‘‘I like to take care of folks. You get to know the customers and what they like. Some you like to crack up. It’s always service with a smile.”

Watson plans on being at her usual spot behind the register of the thrift shop tomorrow on the anniversary of her 20 years, celebrating the only way she knows how, with continued service.