Additional income not only provides peace of mind, but it also means you need less money to retire on.  If your side business provides you $3000 a month, and you need $7000 a month to live on in retirement, you may be able to retire 5 or 10 years earlier than you otherwise might.  Instead of a $2.1 Million portfolio, you may only need $1.2 Million.  This, of course, assumes you’re willing to keep running the side business.
Now I’ve been using Swagbucks for a while and have found the money works out to just under $2 an hour so this isn’t something that’s going to make you rich. You’d have to work 2,500 hours to make $5,000 so that’s about three and a half months, non-stop. The thing with Swagbucks though is you can do it when you’re doing something else so I flip through surveys and other stuff while I’m cooking dinner or flipping channels.

Residual income is calculated as net income less a charge for the cost of capital. The charge is known as the equity charge and is calculated as the value of equity capital multiplied by the cost of equity or the required rate of return on equity. Given the opportunity cost of equity, a company can have positive net income but negative residual income.