How Much Money Is “Walk Away From It All” Money?

Roger writes in with an interesting question: When you talk about “walk away from it all” money, how would you estimate that? I know it would be different for each person, but what elements do you take in mind, and what percentage of savings or what size emergency fund (24 months of living expenses, for example?) would you constitute reaching that point? Before you even start looking at this, you need to have a very strong bead on your realistic spending over the course of a year. What do you