Traveling is expensive overall, but one of the biggest costs associated with a trip is often the lodging.

Studies have suggested that the best time to buy a plane ticket for lower-price options is 70 days in advance. But does the same reasoning apply to hotel rooms?

HuffPost spoke with travel booking experts to get the skinny on hotel room rates.

How Far In Advance Should You Book?

It may feel counterintuitive, but the key to getting a good rate is often waiting until the last minute to book a hotel room.

“Hotel providers would rather a room be occupied at a lower rate than be unoccupied, meaning the price drops the closer it gets to your stay date pending how much inventory is left,” said Mel Dohmen, a senior brand manager with Orbitz.

In this sense, hotel rooms are very different than airline tickets.

“It comes down to basic supply and demand,” said Devon Nagle, the head of communications for Priceline. “There are countless more hotels than there are airplanes. As flights fill up, seat prices rise. The same isn’t necessarily true for hotels ”• they compete on price every day and regularly lower their rates on any given evening to try and secure last-minute bookings.”

Analysts from Priceline looked at hotels across all star ratings booked on the site from January 2018 through September 2019 in California, Florida, Texas, Illinois and Massachusetts. They found that last-minute bookings were regularly much less expensive than those made further in advance, according to data Nagle shared with HuffPost.

“The ‘sweet spot,’ in fact, was one day prior to check-in across all five states,” he said. For example, the average rate for Massachusetts hotels booked 90 days out was $244 per night, but the rate fell to $205 at 40 days out and $141 one day in advance.

What Time Should You Book?

If you’re able to book at the last minute, even the time when you make your reservation can affect the rate. In fact, being spontaneous and waiting until the very last minute can pay off in a big way.

“If you can wait, the best time to book is typically same-day,” said Sam Shank the CEO and co-founder of HotelTonight, a discount travel app that specializes in last-minute bookings.

“On average, same-day hotel rates are 10% less than booking the day before and then typically drop dramatically around 4 p.m,” Shank added. “If you book at 8 p.m., you can usually save another 5-10%.”

When Is Last-Minute Booking A Bad Idea?

Of course, booking last minute isn’t always the best approach.

“The downside to this money-saving tactic is you are taking a gamble and risking that inventory might be sold out the longer you wait,” Dohmen said. “So if you want to make sure you get a room at your favorite hotel or stay at the same place as your friends, this may not be the right tactic for you. This is particularly true if you’re booking a hotel for a popular event, as inventory tends to sell out much further in advance.”

The last-minute approach is not a hard and fast rule, agreed Joel Brandon-Bravo, the vice president of TransPerfect and former managing director at Travelzoo UK. Many factors specific to certain hotels and their pricing strategies can affect supply and demand. A group booking could cancel, leaving the hotel with many unsold rooms, or a large conference at the hotel may make rates higher.

“If the revenue manager ”• whose job is to set rates ”• thinks the rooms will sell, they’ll set the price higher. If they’re right, they’ll stay high — or even go up. If they overestimate demand, then as the stay date approaches, they’ll drop prices,” Brandon-Bravo said. “We saw this in London for big events like the Olympics and the Queen’s Jubilee when hoteliers mistakenly forced people to book three-night minimum stays at high rates and then had to panic-sell them at low rates when people didn’t book.”

Ultimately, flexibility is important when booking hotel rooms. Travelers should consider where and when they might want to go and make decisions based on demand, Brandon-Bravo said.

“You could look today, look in a week and see which way it’s trending and then ride the trend, booking now if it’s gone up and waiting if it’s heading south,” he said.

What Day Of The Week Should You Book?

If booking same-day or one day in advance aren’t options for you, there are other factors that can help you get a cheaper rate. Historical booking and pricing data suggests that travelers should hit “confirm” on a hotel room on particular days of the week to get better deals, although the most opportune days may be different.

“The average daily rates on hotels vary across different reservation days,” Dohmen said. “Our data shows travelers generally find the lowest ADRs on Fridays. Unlike airfares, the most expensive day to book a hotel is generally on a Sunday.”

Nagle’s data, however, showed otherwise.

“Priceline analysts found that the best day of week to book a hotel for the lowest prices was on Sunday,” Nagle said. “The second-best day of week to book a hotel was Monday, and the difference was not large.”

It may be worth it to take a look at the rates that show up for hotels when you search on different days of the week to determine any trends for your preferred destination.

What Days Of The Week Should You Stay?

The days of the week you’re planning to stay in the hotel also play a big role in determining the price. For example, if you’re able to be flexible with your dates, you may want to consider staying over a Sunday night.

“Sunday night hotel rates are, on average, 30% cheaper than Fridays and Saturdays, so we suggest shifting your weekend from Friday-Sunday to Saturday-Monday,” Shank said. “With this strategy, you can also take advantage of less crowds and easier access to amenities and restaurants.”

Brandon-Bravo agreed that Sunday night hotel rooms tend to be cheaper.

“Those on a weekend break have headed home to get ready for work the next day, and most business custom is midweek,” he said, adding that it’s also helpful for travelers to consider the “Saturday Night Rule” when booking flights to save money as well.

What Time Of Year Has The Best Rates?

Although hotel rates vary by day, the season also makes a big difference.

“The simple rule to saving money is go when others don’t. The hotel is there all year round, and often the flights are, too,” Brandon-Bravo said. “Empty rooms and seats can’t be sold the day after! They lose money or break even in low season, and they hike prices when demand is high to make money overall.”

He recommended taking city breaks over Christmas or midsummer when business travel and crowds are at a low.

Oftentimes, the optimal time to book a hotel is “shoulder season” ”• the time between the high and low (aka peak and off-peak) seasons.

“Generally, we find hotel rates are cheapest in early January and February after peak holiday travel season winds down,” Dohmen said. “Most people aren’t looking to travel after taking time off for holiday travel, so rates tend to be quite low. In the summer, September can be a great time to book a beach vacation on the cheap since the busy season tapers off once school is back in session.”

Nagle noted that the good weather tends to hold during shoulder season, even as the hotel prices fall. Priceline’s analysis showed that the average rate for hotels in Wailea, Hawaii, is $542 per night in the summer but falls to $403 during shoulder season. In Myrtle Beach, South Carolina, the midsummer hotel rates average $181 per night, but in shoulder season, it’s $107 per night.

“High seasons obviously differ by destination, but overall in the U.S., summer rates tend to be highest and winter rates tend to be lowest,” Nagle said.

“Don’t be shy of calling or emailing the hotel directly,” Brandon-Bravo added. “They’d usually be happy to tell you when you can get a deal, as they want to fill empty rooms and may throw in an extra — or at least price match anything you’ll find elsewhere. Some offer a calendar view of rates, so a simple scroll through will give you an indication.”

How Else Can You Save?

There are many other ways to find good deals on hotel rooms. Consider opting into email lists and loyalty programs from your favorite travel websites, Dohmen recommended, and pay attention to sale days like Black Friday and Cyber Monday.

Travel deal websites sometimes offer better rates with special packages in quieter months, which can be useful (if not a bit limiting on choice), Brandon-Bravo said. Still, he cautioned against falling for messages on online travel agent sites that say things like, “only two rooms left” or “this room was booked 2 minutes ago.”

“It’s often simply not true,” he said, adding that hotels and online travel agents in Europe have recently faced consequences for misleading customers.

Booking directly through hotel chains and joining loyalty programs can also lead to lower rates and even benefits like free upgrades.

“Hotel chains also don’t like paying hefty commissions to OTAs like booking.com, hotels.com and Expedia, so [they] will often incentive you to book direct,” Brandon-Bravo said.

Ultimately, the biggest misconception about booking hotel rooms is “that there’s a simple rule to it.”

“There just isn’t,” he said, pointing to the many different factors that affect rates. So instead of looking for a magic number, it’s best to just accept that it doesn’t exist and be open to different options.

“If you want a deal, be flexible with where and when you go,” Brandon-Bravo said. “Then you can get a five-star vacation at three-star prices.”