That said, if you are looking to book an apartment close to the date you're traveling, ask about last-minute deals and off-season specials -- rental services and owners may slash fees in order to get heads in beds. But if you're worried about losing your prepaid deposit or rental fee, consider purchasing travel insurance before you leave home.

Are customized, hotel-like services even available?

So you've chosen to rent an apartment for all the great reasons above, but perhaps you don't speak the language in the country you're visiting. You're geographically challenged, would get lost inside a paper bag and need help getting around town. Or you're dying to book that super-hot small restaurant you read about but need help nabbing a reservation.

In these cases, a hotel concierge would be really handy -- but you're staying in a flat. Some upscale apartment rental services happily provide their guests with concierge services on demand (and often at an additional cost, but not always). For example, Santa Barbara Vacation Rentals in Southern California offers a free grocery shopping and delivery service for guests who complete a list 72 hours before check-in, and the items will be waiting in the unit when they arrive.

Starting at 125 euros a day, Parler Paris Plus in France will create personalized itineraries. They can also plan private yacht or helicopter rides along the Seine River, book Paris market or antique tours or for 75 euros an hour will run errands and purchase gifts for those guests who'd rather spend their Parisian hours being tourists.