Initially, we grow our assets by savings. Investing these savings over time then starts to accumulate assets in terms of yearly incomes. A simple 10% saving rate, if not invested, will accumulate one year's income in 10 years. While with investing, it will do so in much lesser period depending upon the rate of investment return. Then one day, we see that we have assets worth income of multiple years. And after some years, the yearly growth of our assets can become equal to the yearly income. At this point in time, we have reached the Critical Mass. And now the possibility to retire from a day job / salaried job is a real possibility.