This Common Vacation Mistake Could Be Costing You an Extra $689 (Video)

There's nothing better than that care-free vacation feeling — but it turns out your nonchalance could be wreaking more havoc on your wallet than necessary.

New research shows that more than 1 in 10 travelers don't keep track of what they spend while on vacation, and almost two-thirds have trouble budgeting their money while they're away.

Air Travel Organisers' Licensing (ATOL), a U.K.-based financial protection scheme for vacationers, found that we underestimate our spending while on a trip by £536.80 (that's about $689) on average.

Among the largest causes of this, according to ATOL, are food and drink expenses. While some travelers are arriving at their hotels expecting more to be included than actually is, according to the Mirror, others are simply not properly budgeting for their meals.

The best way to avoid this? Call beforehand and clarify what comes with your stay, and have an idea of what you can spend before you go out for dinner or cocktails. If you don't trust yourself after a few margaritas, don't bring a ton of extra cash out with you.

In addition to meals, going into each day with an idea of how much you can afford to spend overall is always a good idea. Simply calculate the total amount you're okay with spending on your trip, and divide it by the number of days you're going. Allot more of an allowance on days when you have more expensive activities planned, like guided tours, a fancy dinner, or an excursion to a shopping district, but then cut back on overpriced cocktails and other unnecessary expenses on those other lazy days at the beach.

Another costly common mistake, according to the study, is withdrawing cash from foreign ATMs instead of getting the best exchange rate in advance. Local ATMs are likely to hit you with extra fees galore, so check the specifics with your bank before you make that withdrawal, and arrive prepared.

And finally, unexpected transportation fees are cleaning us out, as more airlines charge for "extras" like carry-on baggage and choosing a seat (it's easy enough to check policies online before you book your ticket) and we tend to forget about minor costs that can add up fast, like taxis and parking.

There's sometimes no avoiding a spur of the moment need for a taxi, but consider keeping notes on what you're spending in your phone so you can adjust your budget accordingly.

Staying on top of your finances isn't exactly what we call a fun time, but keeping track as you go will save you a whole lot of regret when you get home. Almost $700 of regret, to be specific.