I took a year off to do this when I got out of the Air Force in 2008.
www.Adamandshawn.wordpress.com It's not like your one-week major destination resort kind of "vacation". You can travel in 75% of the world for far less money than it takes to just live life in American, Australia, or Western Europe- it's a different mindset than a typical vacation. In that year, I spent $50-60k for TWO people, $13k of that being the mortgage on the house I couldn't sell, another k or so for insurance, $6k each for flights, and a few expensive splurges (Galapagos, Bhutan, diving trip in Aus)...figure $13k for those. So...HALF that money was in splurges and home expenses...the rest was quite cheap. Indonesia, for example...we were living for like $750/ month....COMBINED! This was at the peak of the recession (which is why I couldn't sell my house), and the exchange rate SUCKED....like $1.75/euro
The dirty secret of long-term travel though is burnout. By the time I got to Buenos Aires....via Europe, Asia and Australia, I just got an apartment for a few weeks and sat on ass. Didnt' even want to hassle with a side trip to Iguazu falls. It's a slower pace than vacation travel, but the constant planning and uprooting every couple weeks takes a toll. Ideally, you'd want to do this in two two-month blocks per year, and run a business back home the other 8 months.
I'm still tempted to do it again to make a video like this! At least I have my travel blog. Alternatively, a 34 year old friend of mind, by living a very modest lifestyle, has just RETIRED from full time work. He's going to do rock-climbing guiding on the side. Another very modest lifestyle friend is retired in his early 40's. He only made like $26/hour.
I'm getting very tempted to sell it all and live modest. Bimmer and all. Living out of a daypack and a roller for a year makes you realize how little we actually need our stuff. I can get a Subaru and perhaps a motorcycle for fun.