As hundreds of thousands of people flee Hurricane Dorian's potential impacts in Georgia and the Carolinas, others will stay behind and hope for the best.

The same thing happened in Florida earlier this week – many left, but many did not.

"People are going back and forth, they're taking in a lot of information," Samantha Montano, a psychologist who specializes in emergency management and disasters, told weather.com. "They're thinking about what that information means, how that affects their family, whether they trust where that information is coming from."

(MORE: The Latest Forecast for Hurricane Dorian)

Myrtle Beach resident Nikki Betush told the Greenville News her family was staying, confident that their canned goods, batteries and water will see them through. Tuesday afternoon, she picked up sandbags from the city.

"We've got critters, so evacuations are never really an option for us," Betush said.

While many shelters do allow pets and some hotels in evacuation areas waived pet fees and restrictions, Betush has three dogs, two cats and two fish tanks. Add in her two teenagers, she said, and the family would need four vehicles to get everyone out.

"So, it's always hunker-down mode," Betush said.

Ruth Quinn spent Monday night at a shelter in Myrtle Beach, but decided on Tuesday morning to return to the comfort of her own home in Conway.

"I can always come back," she said.

More than 800,000 people are under an evacuation order in South Carolina, but there is no penalty for not leaving and officials can't force people from their homes.

By Wednesday afternoon, only about 360,000 had left. Many in the area were experiencing "evacuation fatigue" after consecutive years of hurricane evacuations, according to the Greenville News.

South Carolina Emergency Management Division spokesman Derrec Becker told the paper that might be a factor in why evacuation numbers weren't higher. The paper also reported that only 60% of those ordered to evacuate last year for Hurricane Florence left, and in 2016, 50% of those told to evacuate for Hurricane Matthew left.

(MORE: South Carolina Feeling First Effects of Hurricane Dorian; Death Reported in North Carolina)

On the other hand, Montano said, some people are more likely to go if they have previously experienced a hurricane firsthand, even if they aren't under an evacuation order.

"Some people say, 'I'm never doing that again,' so they want to get in their cars and leave," she said.

While such "shadow evacuations" can clog roadways and fill hotels with those who may not really be in danger, Montano said everyone's thought process is different.

"People are making decisions that they think are best for themselves based on the information they have," she said, adding that those who are pregnant or who have young children or are elderly may be more likely to choose to leave.

Those factors also come into play for those in evacuation areas, like Jonathan Proferes and Allexis Petrelli, who left their home in Cocoa Beach, Florida. On Tuesday night, they were at the Rosen Hotel in Orlando with their young son Dominic and two dogs in tow. They were under an evacuation order, but considered not leaving. Besides Dominic, Petrelli is pregnant.

"If it wasn't for the little ones, I would have stayed and rode it out," Proferes told weather.com.

In Irma, he said, his family evacuated because his grandmother was dependent on oxygen.

Not everyone can afford to stay in a hotel, but they don't want to go to shelters. They also might not have transportation, or don't have the money for gas to get to a friend or relative's house.

"It's shockingly expensive" to evacuate, Montano said.

(MORE: In Bahamas, Humanitarian Crisis Unfolds on Islands Ravaged by Hurricane Dorian)

Sherry Estrada, who lives near the beach in Volusia County, told NBC News the cost of evacuating combined with the expected missed wages from her job made it impossible to leave when her neighborhood was evacuated earlier this week.

"The only people on this block who left have the money to do it – a dentist, a pilot, an anesthesiologist," Estrada said. "I’m a hairdresser and am not going to be able to work this week. My son-in-law owns his own business. My daughter is a nurse, so she’s on call. I have another son who is an electrician, and he’s not working this week. My other daughter is a waitress, so this was supposed to be a big shebang weekend for them. They’re losing that money. My husband’s a machinist, and his work probably won’t be open."