How soon to book airfare?

Four months ahead of time was the golden hour for booking airfare. You knew it was because that's what the travel books told you. Four months minimum, with six to eight months even better.

What the books forgot to tell you is how much you'd save by booking four months ahead of time. I tracked airfare prices for more than 10 years and found the amount saved to be quite small - sometimes as little as a dollar.

So yes, you might save some money by booking four months ahead of time, but it might be less than you'd need for even a bag of chips at the closest vending machine.

Obviously, if you decide to go to a popular place like London at a popular time like Christmas, you're going to pay more no matter what.

But if you're looking at the shoulder season (April, May, September or October), or better yet, the low season (November through March, except for obvious exceptions like Christmas and New Year's), there's little difference between four months and three months.

What's more important is which airport you use and when (which day of the week) you'll travel. We're within driving distance of five international airports, although only one has airfare rates that get us planning. Tuesday, Wednesday, Thursday and Saturday tend to be lower-cost days, because fewer people want to travel then; you're likely to find fewer passengers and lower rates. By contrast, Monday, Friday and Sunday tend to be higher-cost days, because more people want to travel then; you're likely to find more passengers and higher rates.

Track your flights from different airports on different days, and let your personal finances determine when you buy the tickets. Check out my related post, Find inexpensive airfare, which explains this more fully.

Just be sure to use a credit card, which offers refund protection a debit card doesn't, and get travel insurance no matter what.