Residual income is different from a salary, or linear income, which is paid out strictly based on the number of hours a person works. Someone who works on a salary is often said to work “paycheck to paycheck.” This is because he pays all of his bills with his first paycheck and then must wait until he gets paid again to have more money. Ideally, someone will work hard building up a business so that he can enjoy the residual income once his goals have been met. Then he can work on additional projects while still earning money from his business.
While some have degraded the meaning of passive income with cheesy ,get-rich-quick type schemes, it doesn’t mean getting something for nothing. Whether it is investing hard earned capital, sweat, time, or providing a service such as housing, there is a lot given to create passive income. Each party provides something of high value, even if the end product means simply buying income property.

A different definition of residual income is that this is income derived from passive investments, rather than from a person's active income-generating activities. Examples are interest income, royalty income, rent, and increases in the value of investments held. Individuals typically work throughout their careers in order to build up a sufficient amount of this income to support them during their retirement.
Owning property can earn you passive income for decades to come. Once you purchase a duplex, home, or apartment building as a rental property, you’ll earn a consistent monthly income with little work. Rent should cover your mortgage, taxes, repairs, and other expenses. You’ll continue to earn income by paying off your mortgage with the rent money and saving excess rental income.

Managerial accounting defines residual income in a corporate setting as the amount of leftover operating profit after all costs of capital used to generate the revenues have been paid. It is also considered the company's net operating income or the amount of profit that exceed its required rate of return. Residual income is normally used to assess the performance of a capital investment, team, department or business unit.