As we approach the holiday season, many people will begin planning their end-of-year vacations. Perhaps you’re contemplating a trip to somewhere warm or traveling to see your loved ones. Either way, it’s a good time to start thinking about where you want to go—and how much money you have to spend.

Timing is everything when it comes to travel. Everybody knows that buying airfares in advance will save you big bucks—but how far in advance should you make the bookings? Are there any special days or times you should be hitting the airline websites? There are more myths and rumors surrounding this topic than just about anything else to do with travel, but we’ve done the research. When you’re looking to book, keep these tips in mind.

The 21-day advance
If you have the ability to book your flight more than 21 days before your departure, you have a great chance to scoop the biggest savings. Many airlines use a discount cycle that increases incrementally—the closer to the date, the more you’ll pay.

Can’t make 21 days? Obviously, giving the most notice possible is advised, but many airlines use additional discount tiers with intervals of 14 days, seven days, and three days. Booking on the day of your flight can sometimes result in absolute last-minute bargains, but more often, it will leave you waiting for someone else to cancel.

Tuesday and Wednesday
Traditionally, these are the cheapest days to travel by plane. Vacationers have returned from their weekend destinations, and most people who travel for work have headed off on Monday. By Thursday and Friday, people have started taking their long weekends, and the end of the week is the most convenient for most people to travel, which means it’s also the most expensive.

If you have the flexibility to travel on Tuesday or Wednesday, you can save money on flights, as cheaper rates will often still be available right up until a few days before take-off. An added bonus: Because the plane will be less full, the chances of you having an empty seat next to you is higher, and airline staff are often more attentive, as there are fewer people to check on.

The stroke of midnight
A persistent myth suggests that Wednesday at midnight is the golden time to book your flights. If it’s not Wednesday, it’s midnight Thursday or midnight Friday. There are just as many people who swear by these times as there are those who think it’s ridiculous.

However, some airlines do send out fare updates three times per weekday (and once each on Saturday and Sunday). If you’re a believer that the early bird gets the cheap tickets, head to your airline’s website just after 10 a.m., 12:30 p.m. or 8 p.m. Eastern, Monday through Friday. On weekends, the data is updated for each airline at 5 p.m. Eastern but not uploaded to the website until midnight the following day.

Friday’s all right
While the Wednesday night argument has been debunked as often as it has been proven, there is another day to keep an eye on. At the end of each week, airlines often experiment with prices. Some may drop their airfares to see if the others follow suit. That doesn’t automatically make Friday the best day, though—other airfares can experiment the other direction by raising ticket prices to see if its competitors will do the same. Even if one airline drops its prices on Friday, rivals may not drop theirs until Monday or Tuesday.

Any day ending in ‘y’
Unfortunately, there are no hard-and-fast rules about when to snag the best airfares. Cheap tickets can be released at almost any time of day, any day of the week.

Rather than playing the calendar game, it’s often a much better idea to subscribe to your preferred airline’s online mailing list. The airlines send out discount deals, bonus offers, and occasionally package holiday information that isn’t offered to non-subscribers. Sign up for a few mailing lists and potentially a few aggregator websites as well, to keep your bases covered. A cheap flight’s a cheap flight, regardless of which carrier it’s with.

There are plenty of people who will sing the praises of last-minute bookings, and indeed, there are some bargains to be had. However, if you want to minimize your stress (and maximize your savings!), it’s often best to plan ahead.

Travel Mysteries: What’s the best time to book an airline ticket? The Saturday Evening Post

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Cartoons: Airline Travel The Saturday Evening Post