It's no secret I'm a fan of couchsurfing. Finding hosts online to put you up in their living rooms sounds sketchy, but I've never had a real negative experience. The value isn't just in a free place to crash. The biggest plus is meeting incredible people, real people who can show you a side of their city that you normally wouldn't see as a tourist.

For me, that meant everything from a house party in Paris to sipping beers in Munich while discussing German historical consciousness. Oh, yeah. And staying for free.

Here's how to crash with strangers around the world, without landing yourself in a shady situation du jour:

Be Discerning
When I was traveling alone in Europe in my early 20s, I set specific guidelines: I limited my search to women in their 20s and 30s with good English and favorable reviews from former guests. Luckily, I was traveling in populated areas with lots of options for hosts, and I used that to my advantage. You can actually filter your results by certain criteria like language skills, something I thought was important as someone traveling alone, so there were no misunderstandings.

Have A Backup Plan
You never want to be beholden. If you get a bad vibe, be prepared to leave. The best bet is a list of hostels or hotels in the area. It's great to save on accommodations, but if you feel weird about a certain place, suck it up and pay. The closest I got to a bad situation was when I showed up at a host's house and she told me I could stay in her roommate's room, and use her roommate's laptop. I gladly obliged ... until her roommate came home and they started a screaming match. I was prepared to up and leave. Luckily, the roommate said it wasn't my fault and I slept in the living room. Needless to say, I cut my tenure short by leaving first thing in the morning.

For frequent travelers, it's the Holy Grail: a free flight, a free upgrade, the ability to say, "Oh, this? I got it with my airline miles."

But when push comes to shove, are credit cards that give you airline miles really worth it?

Let's go point by point.

Value For Your Money
Running the math requires making a few assumptions, but here's a rough sketch.

Option A: Let's say your travel card gives you a mile per dollar you spend. Let's also say that it takes 25,000 miles to get a free round-trip domestic U.S. flight, which is the going rate at airlines like American and United. Obviously, the dollar value of a domestic flight will vary, but for argument's sake, let's call it roughly $500.

To earn the 25,000 miles you need, you'd have to spend $25,000. If that flight is normally worth $500, you're getting back 2 cents on every dollar you spend.

Option B: Let's say your cash-back card gives you 5% back on certain categories of spending, and 1% back on everything else, pretty standard for its card type. For the sake of our math, let's say, on the whole, that averages out to roughly 3% back per month.

Instead of using miles, you want to earn $500 to buy your ticket the old-fashioned way. At an average of 3% back, you'd have to spend just under $16,700. That comes out to about 3 cents per dollar.

The outcome? If these numbers hold true, you're getting better value with a cash-back card.

Of course, not all cards are created equal. If you found a travel card offering 2 or more miles per dollar, then that card would beat most cash-back cards. Try it out with your own numbers with these basic equations:

It's little surprise that China is crowded. Given a booming population that can afford to fly – and without an equally booming plane population – researchers in Beijing have been examining ways to make boarding planes most efficient.

The idea is to accommodate the heightened Chinese flying demand and relative scarcity of planes. Western Australia's ScienceNetwork reports that researchers are doing something new by looking into boarding patterns, as opposed to just luggage congestion and takeoff scheduling.

The findings? Move over, screaming children and slowpokes.

The researchers found that there is an "optimal" way to board a plane, and it involves categorizing passengers by their "individual properties."

Under our current model of assigned seating, passengers at the front can reach their fastest possible boarding speed, but after that things slow down. The "optimal" system would categorize you by your luggage type, timeliness at the gate and other factors, and sort you into boarding order that way.

Although this is nice in theory, there are some obvious problems. Math can't, after all, account for factors like passengers' personalities, how distracted they are or even how large they are. Oh, and the fact that humans aren't generally as predictable as variables in an equation.

[Image credit: Flickr user Reuben Whitehouse]

One of the hairless cats cozied up to me. The other looked on, like a bald alien. My friend and I were sitting on a leather couch, listening to a guy we'd just met share intimate – and disturbing – details of his sex life.

I was traveling with a guy friend through this leg of my Europe trip. I'd stayed with a few couchsurfers before. When I was traveling alone, I'd always been careful to choose hosts who seemed safe. Read: nice, sweet-sounding women in their 20s or 30s.

Traveling as a pair presented new challenges and opportunities. First, a lot of those reliable-sounding hosts only opened their places to a singular guest, so it ruled out a whole demographic of non-axe murderers. But, on the upside, traveling as a pair – especially when one of us was a guy – meant I also felt more comfortable staying in a place of a shadier persuasion.

London, obviously, can be very expensive for travelers. So the first order of business was finding a reliable couch to crash on.

A guy I'll call Wes offered to host us. He was from Italy, but spoke with a perfect British accent (to my American ears, at least). His job was in fashion, and he sported a mohawk with buzzed-out designs all over his head, black leather pants and jacket, and extremely tall platform shoes. That description sounds Marilyn Manson-esque, but there was no makeup. Wes noted that most fashion stylists were gay, but wanted to make it very clear that he wasn't. He just liked his own style.

Wes lived near Kings Cross, and met us at the station before taking us to his favorite Chinese dive. The food was good and cheap, and that was the point.

Next, he took the two of us back to his apartment. We put our stuff down, set up camp in the living room, and, without any bidding I remember, he began to tell us about his sexual escapades. I'm nearly positive he wasn't planning on inviting us or anything, but perhaps he wanted to impress us.

Given the ever increasing, uh, size of air passengers (not least American air travelers), airlines are cracking down on passengers who may just rather roll up their armrests and encroach a little on the space of other passengers next to them.

The ongoing debate has been around whether larger passengers are, and should be, required to buy extra seats for themselves, and the jury is coming back with a definitive "yes." Yahoo! News rounds up policies from major airlines on "passengers of size," whether there are special provisions, if fees are required, and, basically, what the deal is.

After going through the options, we can weigh in on the best and worst.

The winners? Customers of some size may want to opt for JetBlue, which has slightly larger seats than most other airlines. Usually airlines provide about 17 inches between armrests, but JetBlue provides 17.8 inches.

If you're a customer of the next size up, your best bet may, surprisingly, be Spirit. Although Spirit is known for nickel-and-diming its customers with loads of different fees, paying extra for a Big Front Seat may actually be worth your while, rather than buying a whole extra seat like you'd have to on another airline. In addition to offering 6 extra inches of legroom, Spirit's Big Front Seats are 18.5 inches wide.

If you're a customer of a larger size than that, your best bet may be Delta, which doesn't require you to buy an extra seat. Delta will simply give you an extra seat next to you ... if one is available. Obviously, the downside is if you're in a rush and there are no spare seats on the plane. They'll put you on another plane with extra room, but you may have to wait. In that case, it's your choice to buy an extra seat for yourself in advance.

The loser? United. If you fly on United, you have to prove the armrests go down and stay all the way down – even if you're seated next to family. While I totally understand (and agree) that it's inappropriate for strangers to intrude on other passengers' spaces, other airlines make an exception if you sit next to family members who don't mind. No such luck on United. You can purchase your extra United seat in advance, and if you don't, you may be charged additional walk-up fees later.

[Image credit: Flickr user sbamueller]

Being in a new country is full of enough culture shock – trying to remember how many dollars to the krona doesn't need to be part of it.

After all, constantly whipping out a calculator (well, a cellphone) and spending five minutes trying to figure out if that sandwich is really a good price is a waste of your valuable vacation time.

To make things easier on you, here are some basic rules of thumb to help you guesstimate the exchange rates in a sampling of different countries.

It's important to note that currencies fluctuate all the time, so these rules of thumb should not be used as actual foundations for financial transactions. They were based off the most recent exchange rates as of midweek on the week of November 5, 2012. If you actually want to know what the exchange rate is for a given country, look it up. And if you want to know again a week later, look it up again.

These rules of thumb are intended to help you quickly do the mental math required to figure out if, yes, that sandwich is a good deal. Or, when you withdraw 400 pesos from the ATM, roughly how much you're taking out in US dollars.

Disclaimer: this post is admittedly America-centric, but the reality is that's my perspective as a traveler. I hope this will help others as it's helped me.

The meteorological ladies have it out for the Northeast. First there was Sandy, and now there's (winter storm) Athena.

Planning on going there anytime soon? You might need to wait a little longer than you think. With Athena The Nor'easter on its way to the Atlantic states, parts of New England flights are being canceled left and right. Regulators obviously learned a lesson from last week's Hurricane Sandy.

On the ground in New York City, I see snow/slush flurries outside my window. The weather forecasts wind gusts over 30 mph later today in my neck of the woods in Brooklyn with heavy snow in the early evening. Nantucket, meanwhile, is expecting gusts over 50 mph. The areas with the heaviest snow are expected near the Berkshires and the Catskills.

In other words, if you were planning to travel right now, you might not have a choice. News outlets report that airlines have canceled about 1,200 flights, following more than 20,000 flight cancellations last week from Sandy.

As areas without power and heat brace for a winter weather terror, there are a few things you can do to help Sandy relief. If you are in the greater New York/New Jersey region, you can find volunteer opportunities here. In particular, areas without power or heat are particularly susceptible to Athena, since many have only tarps to protect them from the winter winds and cold. Whether you're in NYC or elsewhere, a group has created an Amazon Wedding Registry list with supplies needed for the relief effort.

So what should you do in place of heading out to catch a flight bound for NYC? Maybe do some online shopping instead.

[Image credit: Flickr user NASA Goddard Photo and Video]

Everyone dreams of the absolutely perfect vacation. A whole year away. Sampling amazing cuisines every night. Five-star hotels everywhere. Screw the cross-country bus, you'll take the bullet train!

All of that can be yours, at a cost, of course.

Planning a vacation is all about balancing variables. Think of it as a triangle between cost, time and luxury – you can have two, but never all three.

So:

• If you want a yearlong trip in the lap of luxury, that's fine ... you'll just have to sacrifice your budget.
• If you want a luxurious trip without spending a ton, that's fine, too. You'll just have to sacrifice duration, like staying just one night at a fancy resort.
• Want to go away for a long time without blowing all your cash? Great, it looks like you'll be backpacking and staying in hostels for a while to come.

This is particularly important in the planning stages of your trip, when you're deciding where to go and for how long. After all, if you planned for two weeks in an expensive country and realize halfway through that you're going to go over budget, it's a little too late, isn't it?

The key to staying on budget is to figure out how you'll allocate your resources by working the ratio of those three factors: cost, duration and how much you'll spend on the ground. Think about what matters most to you and then hold yourself to it as best you can.

Based on personal experience as both a traveler and a personal finance writer – and a significant amount of number crunching to make sure my calculations make sense – I've come up with an equation to figure out just how much trip I, or you, can afford.

December might be a cold, dour month in a lot of the country, but not in Miami – and for reasons other than just the tropical weather. Art Basel Miami Beach will kick off on December 6, and the New York Post reports that the social scene will be more revved up than ever.

Many of the awesome parties around town won't be directly related to the international art event, but the city will be buzzing with an influx of visitors from around the world – particularly, visitors with money.

The festivities don't end with the Art Basel itself; during the same week, Bayfront Park will be home to UR1 music and art festival, which will have musical acts ranging from hip hop to indie, rocking out on five stages.

In addition to high-rolling parties, the city will showcase new developments. For example, the American Airlines Arena will host VIPs in its new Hyde lounge, and new hotels like the SLS South Beach hotel and the re-branded James Royal Palm will host events.

All of this makes me wonder: (1) What about the supposed recession and Miami's real estate bubble? (2) Where can I get in line?

[Photo credit: Flickr user miamism]