Maybe you change the sheets on Saturdays, watch football on Sundays, call Mom on Wednesdays and grocery shop on Mondays. Creatures of habit tend to have strong opinions about the "right" day to take care of certain tasks, but when it comes to saving money, any day is the right day. For years, travel experts suggested booking plane tickets on Tuesdays because it was then that airlines released their cheapest seats. That's no longer true. Today, it's not just the day of the week but the number of days before your trip that should dictate when you make your reservations.

Monday, Tuesday, Thursday, Wednesday

Sayonara, Tuesday. You're no longer the cheapest day in town. Travel analysts say that Thursday is now the best day of the week to buy airline tickets.

But don't expect that Paris flight you've been eyeing to suddenly drop by $100. The average savings on a Thursday flight could buy you a pizza but not much else, and there's no guarantee that the flights you're looking at will be cheaper on Thursday. In fact, if you look at the same itinerary on your favorite booking site every day for a week, it might not change at all, or the lowest price could appear on Monday or Wednesday.

So if you're shopping for a flight, make sure to check out the options on a Thursday, but don't expect to see dramatic drops in price.

One rule of thumb that still applies is that Sunday tends to be the most expensive day to buy flights. The weekend is one of the most popular times to buy flights, but not the cheapest. Let the last-minute business travelers book their seats over the weekend, and hold off on finalizing your own plans until a new week starts.

Perfect Timing

If finding the best possible price is your main concern when booking a flight, focus more on when you plan to fly and less on the current day of the week. You may occasionally find a great last-minute flight for a low price, but generally speaking, you'll get the best deal if you book your ticket about seven weeks before your desired departure date. If you're flying internationally, you'll probably find the lowest prices a little more than two months out from the departure date.

To make sure you get the best price available, make a habit of using the price comparison tools that your favorite booking sites offer. Start looking for flights at least 10 weeks in advance if possible, and sign up to get email updates when prices drop for the itinerary you want. Then you'll have at least a few weeks of data to consider by the time that seven-week window hits. You'll feel better booking a $600 ticket if you know that it was $750 the week before.