Over my five-year-long study of Rich Habits, for which I drew conclusions from surveys of 233 wealthy individuals on their daily habitsand compared them with 128 lower-earning individuals, I learned that most self-made millionaires generated their income from multiple sources.

• 65 percent had three streams of income
• 45 percent had four streams of income
• 29 percent had five or more streams of income

Having multiple income streams makes a lot of sense. When one stream is negatively affected, for whatever reason, the other streams can help you keep going without dramatically downgrading your lifestyle.

Most people have one stream of income: their job. If you do not save and invest your savings in assets that generate additional streams of income, and you lose your job, you could find yourself losing everything.

Putting all of your eggs in one basket by being dependent on one stream of income is risky. If that basket breaks, what do you do?

In our book, "Rich Habits, Poor Habits," co-author and self-made millionaire Michael Yardney explains how he helped hundreds of ordinary individuals become self-made millionaires by creating multiple streams of income. Here's a list of some of Michael's top tips:

1. Save, save, save: Save 10-20 percent of your net income every year.
2. Learn, learn, learn: Develop new skills that you can eventually turn into a side business. Acquire knowledge that you can use to start up a side business or that can help you intelligently invest your money in assets that generate passive income. Passive investments include: residential rental properties, commercial rental properties, TICS, triple net leases, seasonal rentals (beach areas, ski resort areas, lake front areas), equity investments (stocks, bonds, mutual funds), annuities, permanent life insurance, royalty-generating property (timber, oil and gas), boat rentals, etc.
3. Invest, invest, invest: Invest part of your savings in a side business that will one day generate an additional stream of income.
4. Reinvest, reinvest, reinvest: Once your side gigs begin generating cash flow, reinvest that cash flow to either grow the business or invest that cash flow in other side businesses or assets that generate passive income.

If you can't do it on your own, partner with others and keep building your side businesses or passive investments. That's what self-made millionaires do.

An income stream can be a financial investment. Ashton Kutcher famously invested some of his Hollywood cash in Skype in 2009 when it was valued at just $2.75 billion. Microsoft purchased Skype for more than $8 billion, making Kutcher enormously wealthy.

It can be a real estate property that generates revenue. Arnold Schwarzenegger gets most of his current income from real estate investments he made prior to becoming a movie star, according to "Tools of Titans."

It can be another business, or several, which is a strategy favored by Sir Richard Branson, as he notes in his autobiography, "Finding My Virginity," and by by Elon Musk.

Three streams of income seems to be the magic number for the self-made millionaires in my Rich Habits study, but the more income streams you can create, the more secure your financial house will be and the more wealth you will create.

Tom Corley is an accountant, financial planner and author of "Rich Kids: How to Raise Our Children to Be Ha