Another reason for the longevity of the stalls could be the prices, which are about 20 per cent cheaper than those at the bigger chains.
For example, 1kg of sliced bak kwa at Peng Guan costs $40, while Lim Chee Guan and Bee Cheng Hiang charge $52 a kg. These prices will increase in the lead-up to Chinese New Year.
These stall holders can keep prices low because of their low overheads. Monthly rental rates can range from $500 to more than $3,000.
Mr Ng Thiam Heng, 39, a second- generation owner of Kim Hua Guan, says: "Making bak kwa involves a capital-intensive seven- step process, from marinating the meat to barbecuing it, so I'd rather spend the money on the product than pay rent that is 10 times higher if I were to operate in a stand-alone shop."
Mr Teo Kim Wah, 77, who runs Kim Wah Heong, says the lower rent he enjoys as a first-generation hawker helps support the shop's sporadic sales.
The former butcher says: "Bak kwa is expensive and not a daily necessity. The bulk of our earnings in a year comes from the two weeks before Chinese New Year." Calling this his "retirement job", he adds: "As long as I earn $1,000 to $2,000 a month, I am fine."
These stalls sell 20 to 50kg of pork every day and their sales can increase tenfold during Chinese New Year.
Outside the festive period, they are largely dependent on sales from tourists from Indonesia, Brunei, and Hong Kong, who buy bak kwa to take home. These tourists, who come to Singapore for medical appointments or to visit relatives, frequent these stalls because they can buy bak kwa in bulk, sometimes more than 10 boxes a person, at wallet-friendly prices.
Mr Teo adds that being near a market makes it convenient for customers to buy bak kwa while buying groceries.
However, there are disadvantages operating at a hawker centre. Space constraints is one. Mr Teo says the charcoal grill occupies almost half of his 63 sq ft stall.
He says: "A larger stall space will encourage more young people to enter the bak kwa trade, as they do not need to limit their production scale and can come up with new flavours."
Business can also be slow, which is why one stall holder has diversified. New Eastern (Kim Kee) started selling dishes such as fried prawn rolls and fried intestines alongside its bak kwa 16 years ago. Stall owner Jeff Ng, 57, says: "During the non-festive months, customers can buy bak kwa as snacks while coming to the stall to buy the rolls."
Another bak kwa hawker stall owner has come up with innovative ways to draw customers.
Administrative executive Zhang Ziyue, 29, quit his job three years ago to start Peng Guan. He launched it as a wholesale supplier catering to companies. Encouraged by the response, he opened a "low-budget" hawker stall in May 2014.
To attract customers, he has tied up with deal-buying sites such as Qoo10 and Deal to come up with promotions such as selling bak kwa at $20 a kg with the delivery charge waived.
Mr Zhang says: "I made a loss with such promotions, but they were effective way to get people to try my brand."
To stand out from the competition, he offers convenience and customer service, such as replacing and re-delivering bak kwa if customers are not satisfied with its quality. He says: "It is a way of winning them over so that they remember the brand and drop by the stall throughout the year."
One such customer is senior recruitment consultant Kenneth Keo, 31, who buys 1kg of bak kwa from Peng Guan once every two months.
He says: "Its bak kwa is soft and not too dry and it is a plus point that I can book online and have it delivered to my office whenever I have a craving. It is also convenient to pick up my order at the hawker centre where I go for lunch."
Housewife Lee Lian Soon, 68, who has been buying bak kwa from Kim Hua Guan for the past decade, says: "Once, I queued for three hours to buy bak kwa from Lim Chee Guan. It is not worth the wait as I can get soft and chewy bak kwa here too."
For more Chinese New Year stories, go to str.sg/ZHe7.