The premise of "financial independence" is that you save enough enough money and reduce your expenses enough that you can live for the rest of your life on your

The premise of "financial independence" is that you save enough enough money and reduce your expenses enough that you can live for the rest of your life on your investments. Whether you choose to retire or not is up to you, but the point is that you are 'independent' of sources of income to fund your lifestyle. For example, you could reduce your working hours to spend more time on family or hobbies, or take long unpaid sabbaticals, or bootstrap a business, or just quit working entirely. It turns out that you can safely withdraw 3% a year indefinitely (from a portfolio composed of a mix of stocks and bonds in low-fee index funds) without reducing the the value of the investments in the long run. A higher rate of 4% will decline on average over time but can be enough to survive multi-decade retirements, so that's often a more realistic target. There are tools (e.g. http://www.firecalc.com/ http://www.firecalc.com/, http://www.cfiresim.com/ http://www.cfiresim.com/) to run simulations based on historical market data. At 4% you need a portfolio equal to 25 years worth of expenses. Let's say you spend $60k a year in today's dollars. This works out to a monthly budget of $5k. If you can save $1.5M then that will pay your expenses for 30 years, without any other income, with a 94% chance of success. At 3% you need 33 years of expenses, or $2.0M, and that has a 100% chance of success. This is all based on past data of course (past performance does not imply future performance and all that). These are large sums of money, but it's possible for most professional workers, and especially couples, to accumulate them if they are fairly frugal and make a decent income. The time required entirely depends on what portion of your income you can save (see http://www.mrmoneymustache.com/2012/01/13/the-shockingly-sim... http://www.mrmoneymustache.com/2012/01/13/the-shockingly-sim...). Assuming a constant income, as well as constant expenses while working and after, if you save 50% of your household income it will take 17 years to reach the 4% level. So start at age 30 and you'll be done by 47.