Robin, there was some discussion on this on this comment thread recently:

https://news.ycombinator.com/item?id=14803468

Basically I work about three months a year, then take 9 months off. Spend a lot of time keeping fit, traveling, reading, spending time with family. Spend quite a bit of time in South East Asia - mostly diving. It's worked really well for me.

Feel free to email me if you have any more questions.