Is there a best day to get the lowest price on a flight?

Many travelers think the magic day is Tuesday, long lauded by travel deal sites and various publications, including this one, for its fare sales. Other travelers may have heard pundits declare Wednesday the ideal day. In December, Expedia and the Airlines Reporting Corporation, which processes ticket transactions for airlines and travel agencies, announced that weekends are the new best time.

But is there really a preferred day to buy?

“I just want to drive a stake through the heart of that myth,” said George Hobica, the founder of the deal alert site Airfarewatchdog.com, who has been looking at airfares on popular routes every day for more than 20 years, with the rare exception of a vacation where he doesn’t have Internet access.

There are too many variables at play for there to be a universally ideal day to buy an airline ticket. Price depends on a variety of factors, including the route; the level of competition on the route; surrounding holidays and events (like a convention or the Super Bowl); and the days of the week you plan to fly. During a single week in March, for example, a recent search for a round-trip flight between New York and Miami turned up ticket prices as low as $174 and as high as $314. Besides, nowadays we have fare calendars at our fingertips and websites such as Kayak and Travelzoo that alert us to low fares and sales — and those sales don’t always take place on the same day of the week.

Mr. Hobica pointed out, for instance, that on a recent Thursday, Virgin Atlantic lowered nonstop winter flights to Heathrow Airport in London from John F. Kennedy International Airport or Newark Liberty International Airport to about $504 round-trip. Economy fares had been running $900, Mr. Hobica said, then $800, then they went back up, and after that they dipped to around $680.

Airlines (and the above example is but one of many) are perpetually tweaking prices, making predictions difficult. Expedia said as much in its report. Even though its latest research asserts that weekends have the best fares, consumers who spot a good deal on Thursday shouldn’t wait until Saturday to buy it with the hope that the price will tumble even further. “If you find a fare that looks like a good deal, grab it,” the report said, “regardless of the day of week.”

In addition to recommending the best times of the week to book, Expedia and other sites such as FareCompare publish suggestions about how far in advance of a trip to book to score the lowest fare. For instance, Expedia reported in December that the optimal time to buy an economy ticket for travel in North America is 57 days in advance, resulting in a potential savings of about 10 percent versus the average fare. Recommended lead times for travel to international destinations, including Europe and Asia-Pacific, were even longer.

Travelers shouldn’t think of predictions as rules, though. There are flights to Asia, for example, that are $500 cheaper when booked at the last minute as opposed to months in advance, Mr. Hobica said.

And talking about the “average fare” isn’t necessarily helpful because that doesn’t take into account the quality of a flight. Is it nonstop or does it have a 34-minute connection in a busy, sprawling airport like Atlanta? Is it an 18-hour layover in Dallas that will require you to spend an additional $300 in hotel bills and meals? Are you flying in an aisle seat in a Dreamliner or in the middle seat in a MD-80? And if that cheap ticket you found is on a discount airline like Spirit or Frontier, chances are you’ll have to budget another $30 to $100 to check a bag. In other words, you probably don’t want the average fare.

If you want to sit next to your companion, be a safe distance from the bathroom, put your bag in an overhead compartment instead of the belly of the plane, and have enough time to make a connection, what you really want are good fares that may not be the absolute cheapest, but give you the experience you want.

So how do you find these fares?

Almost every major airline (Delta, United, JetBlue) has a good flexible date search option on its website that you can use to see which travel dates will get you the lowest prices, along with the time and comforts you need.

To search multiple airlines at once, there’s Google Flights, which has simple calendars that allow users to easily see if they can save by flying a day or two earlier or later. The tool offers tips to that end. During a recent flight search for New York to Cancún, a message appeared saying that if I adjusted the travel dates by a few days, I could save $246. While the site has international and domestic flight information for nearly every airline, you won’t find Southwest there, so be sure to look at the airline’s own fare calendar on its website.

To keep abreast of private sales and low fares (as well as hotel deals), you can search or sign up for alerts on Airfarewatchdog.com. Email alerts include low fares for a particular route that interests you, or all of the affordable round-trip flights departing from your local airport.

Because prices are constantly fluctuating, keep checking airline websites and Google Flights to see the latest fares. The ticket price you see before lunch may be different a couple of hours later.

Even after you buy a ticket, you still have a chance to save. If you go to My.yapta.com/airline-refunds, you can sign up to receive free notifications if your ticket price drops. (TripIt Pro has a similar service though it’s part of an annual $49 membership.) With Yapta, if the price drop is greater than the cost of your airline’s change fee, you can call the airline and pocket the difference. If the price drops and you booked your ticket within 24-hours, you can simply cancel the ticket free of charge and rebook at the new, lower rate. And if the price on the ticket you purchased goes up? You have something even better: the satisfaction of knowing you nabbed a deal.