Many people talk about passive income and create the impression that you never have to do anything to keep that income going. The truth is that you will normally have to keep your eye on things if you want it to run smoothly. For example Richard Branson doesn’t run any of the 400+ companies he started but he goes over the numbers each day to make sure they’re performing well and calls the CEO if there are any problems.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.