How are you doing this?

How do a teacher and a bureaucrat afford to travel around the world?  The short is answer is through obsessively collecting frequent flier miles and planning 330 days in advance for the best opportunties to redeem them.  A longer answer is outlined in this Washington Post article by a guy that did a similar trip... though I have some philosophical differences with Mr. Wile (yes, there are philosophies of collecting and redeeming frequent flier miles)... he generally uses a lot of same strategies that we used.  Some of our best strategies have been:

1.  Sign up for credit cards with big mileage bonuses.  Don't settle for 25K or 30K bonus miles.  There are plenty of offers out there for 50K, 75K, and every now and again even 100K miles.  We've earned several hundred thousand miles over the past seven years utilizing this strategy (and yes, without wrecking our credit scores).

2.  Volunteer to get "bumped".  Most of the flights that we do "pay" for, we do so through airline vouchers that we have earned as a result of volunteering our seats on oversold flights.  In five years we have earned thousands of dollars in vouchers on four different airlines. 

3.  Book mileage tickets 330 days in advance.  Most airlines open their ticketing, including their mileage tickets, about 11 months ahead of time.  Booking as far out as possible (for us, often the day ticketing opens) is key in getting one of the few seats that is available through frequent flier miles.

I know these strategies won't work for everyone.  We are more flexible with "getting bumped" and more obsessive about planning our travel ahead of time than most people are able to be... but the tradeoff is a lot of fun adventures and getting to see a lot of the world that we wouldn't otherwise.