Well I know I was vague but I really mean the systematic approach to saving 25X your annual spending, investing to earn over 7%, withdrawing 4% per year, and living forever on that plan. You can spend frugally to get to that 25X number, or save aggressively. I'm drawn to the latter.

>Back to the original intent of the post, even if I save sufficiently I would still be interested in doing useful productive work, there are some real life problems to be tackled

The beauty of achieving FI is that you can work on ANYTHING you want. Including noble pursuits like yours.