When most hear the term residual income, they think of excess cash or disposable income. Although that definition is correct in the scope of personal finance, in terms of equity valuation residual income is the income generated by a firm after accounting for the true cost of its capital. You might be asking, "but don't companies already account for their cost of capital in their interest expense?" Yes and no. Interest expense on the income statement only accounts for a firm's cost of its debt, ignoring its cost of equity, such as dividends payouts and other equity costs. Looking at the cost of equity another way, think of it as the shareholders' opportunity cost, or the required rate of return. The residual income model attempts to adjust a firm's future earnings estimates, to compensate for the equity cost and place a more accurate value to a firm. Although the return to equity holders is not a legal requirement like the return to bondholders, in order to attract investors firms must compensate them for the investment risk exposure.
However, residual income typically has an expiration date, especially if it is being earned through a business. Effort must be continuously put into the business in order for someone to continue to receive residual income. Businesses must continue to market themselves in order to remain relevant. The best way to look at residual income in this sense is that it is a part-time job that earns full-time income.
Residual income is really the best Way of Life. It's a steady, reliable stream of income not directly dependent on the hours you work. Successful investors enjoy such freedom. Successful book authors get paid even when they don't write. The checks just keep coming uninterrupted, even when you relax. This is much better than hourly work. Much better that salaried work. 
First of all, the difference between 2 and 5 years is gigantic! Second of all, there again is no quantifiable evidence to prove the efficacy of that statement. It completely depends on the person, the desirability of the good or service, the competitiveness of the industry, the marketing and manufacturing, and much more. To simply say that across all industries you should expect to break* even in 2 to 5 years is complete unfounded garbage.

If you have expertise in a particular area but don’t want to run an online course through sites like Udemy, creating and selling an eBook may be the way to go. eBookStarter.com makes it easy to design your own ebook, and you can even hire someone to write it for you on Upwork. If you prefer to have someone else design the ebook for you, check out Fiverr.
Logan is a CPA with a Masters Degree in Taxation from the University of Southern California. He has been featured in publications such as Debt.com. He has nearly 10 years of public accounting experience, including 5 with professional services firm Ernst & Young where he consulted with multinational companies and high net worth individuals on their tax situations. He launched Money Done Right in 2017 to communicate modern ideas on earning, saving, and investing money.
Lending Club went public in 2014 and is now worth about $1.7B. They advertise P2P lending returns of over 7% for well-diversified portfolios of over 100 notes. I’ve personally been able to achieve a 7.4% annual return over the past two years in a completely passive way by investing in A and AA notes. Others have achieved a 10% annual return through relatively minimum effort.
I’ve built several businesses since 2008 using one or more of these models. I’ve been featured in magazines and articles across the globe, and since I started my journey I’ve generated over $5M in earnings from these businesses. All of my income and expenses for those businesses dating back to October 2008 have been tracked publicly on SPI.com. You can see 10 years of income reports here.

Residual income can have two different definitions or applications. The first definition, a less common application of residual income, is the money that is left after monthly debts are paid. This calculation is particularly important when a person is seeking financing or a loan based on their income and available money to cover the additional debt. In this scenario, the residual income is calculated by this formula: