The hotel itself may hit you with an unexpected, per-day "resort fee" for use of the pool and other amenities. Beach passes, parking, cab rides or buses are other costs you might not have thought about when you planned your itinerary.

Especially in tourist areas, tipping is more common -- and expected by more people -- than might be the case at home. Be prepared to part quickly with any dollar bills and fives tucked in your wallet.

These extra expenses won't net you much in terms of lasting value and certainly won't be precious memories. But they will exact a toll on your household savings.

3. You'll gladly overpay

There is a vacation mindset that makes even the most frugal sort overspend willingly.

Would you pay $100 for dinner or $150 to see a live show? Maybe not at home, but the minute you hit the Las Vegas Strip or hunker down on a cruise ship, you might not give it a second thought.

Souvenirs can quickly add up, even if the folks at home are likely to get only a momentary kick out of those snow globes and oversize T-shirts.

Would you ordinarily shell out $7 for a candy bar or $80 for a bottle of cheap vodka? Hitting the minibar or calling for room service will impose a hefty surcharge. You may not be thinking about a child's college savings account, however, when the craving for a nightcap or midnight snack strikes.

4. Vacation planning distracts us

Getting away from it all for a week or two is one thing, but the amount of time we spend planning our trips and jaunts is distracting us from more important decisions and work.

A survey last year of 2,897 consumers who got or refinanced a home loan in the past five years, conducted by Harris Interactive for Zillow, found they typically spent only five hours on research. An equal amount of time was spent planning a vacation.

When calculated as time spent per dollar spent, Harris Interactive determined that Americans spend almost 80 times more time researching their vacation than a home loan.

"The last few years should have driven home the lesson that understanding one's home loan is critically important, but mortgages continue to be something that most people don't want to spend time thinking about," says Stan Humphries, the chief economist for Zillow, a real-estate website that provides price estimates on 70 million U.S. homes.

Given a diversion from interest-rate crunching, bill paying or portfolio rebalancing, most will choose the diversion of vacation daydreams.

5. No vacation from debt

Even if you have dedicated savings to provide for your vacation plans, odds are that you'll still plunk down plastic along the way. Those who finance their trip entirely on a credit card have even more to be concerned about.

According to CreditCards.com's Weekly Credit Card Rate Report, the national average for credit card APR is around 14.75%. Unless you pay off those vacation charges immediately upon returning home, that interest will continue to accrue. Making only minimum monthly payments will turn that week at the beach into many months of bills.

Even if you have cash in hand for your trip (or staycation), applying that money to pay down debt would pay off in the long run by reducing the principal (and, as a result, interest) on your other loans. Throwing frugality out the window for one or two weeks a year could keep your cycle of debt going strong.

This article was reported by Joe Mont for TheStreet.