Black Friday is one of retail shopping's biggest days, and the craze seems to be growing each year.
Some retailers, such as Sears, are already running pre-Black Friday promotions, said Steven Kirn, executive director of the Miller Center for Retailing Education at the University of Florida.
"I think last year, Kmart was open all day on Thanksgiving," he said.
He attributed stores opening earlier to increased customer demand.
Not everyone is happy with early opening.
There are more than 140 Change.org petitions to keep stores closed on Thanksgiving and let retail employees spend time with their families, according to Time.
Workers have protested at Wal-Mart stores and warehouses throughout the week, using Black Friday as a catalyst for demanding higher pay, more full-time work and less expensive health care.
Despite protests, about 150 million people said they plan to shop on Black Friday, Kirn said.
He said stores still want to create the excitement of early openings, but are trying to avoid early morning chaos.
"So, it's a way of still offering the values but spreading the customer load out," Kirn said.
The thrill of the hunt for bargains keeps people waking up early and flocking to retailers for deals.
"The whole tactic here is, you pick a few items that are going to be high demand and high visibility and you discount the heck out of them," Kirn said. "And then you're counting on picking up sales in other less highly discounted areas when the people are in the store."
Katherine Hahn wrote this story online.