It took years for Jazams in downtown Princeton to get a handle on when their business was needed and when it wasn't. Now, the independent toy shop in Palmer Square essentially has customer activity down to a science and knows when and for how long to keep the doors open.

Kenneth Sponsler, ThinkStock

Unfortunately, many small-time shops in New Jersey's downtown districts aren't so lucky. They've been battling with the same question for ages: should we stay open later?

Closing at 6 p.m. could upset potential customers, but there may also not be enough of those potential customers to justify the extra hours. After all, money is going out the door each second the lights are still on and the air conditioner is still running.

Joanne Farrugia, co-owner of Jazams, said it takes patience to adjust hours and hope for a spike in business.

"I would say, as a business owner, you have to give it a year," she said. "(Customers) don't come until you change their habits because they don't know you're open, and that takes a year."

Nearly 20 years ago, Jazams was open every day of the year until 9 p.m. The owners gradually got the hint that their services weren't needed so late seven days a week. Now, Jazams closes at 5 p.m. on Sundays and 6 p.m. on Mondays. After the holiday season, the store will remain open until 9 p.m. only on Thursdays, Fridays and Saturdays.

Michele Siekerka, president of the New Jersey Business & Industry Association, said downtown boutique shops are faced with a "chicken or the egg" scenario. Is the demand there, and that's why you remain open, or do you extend hours, and that's what attracts the customers?

But, she said, these businesses won't learn unless they try.

"I think you need the right campaign, and I think you have to be able to deliver it and execute it and maybe take a chance and see what happens," Siekerka said. "And then learn from that, maybe recalibrate and try again."

Siekerka pointed to safety as an added obstacle in the downtown districts of urban cities such as Newark and Trenton. Fewer people are likely to stay downtown in the later hours if their safety isn't guaranteed.