They say that 1.25 million air miles allow him to travel free, implying he can do it forever. But, at 60,000 miles for a flight from the US to Asia, and a family of 4, you can burn through the miles in 2 years.
The article mentions that he keeps earning more miles by paying attention to every promotion out there, and has over 4 million now. I also wouldn't be going straight from US to Asia; I'd be hopping locations gradually for an extended vacation to get the most out of the miles.
