Which all goes back to my point – since companies change in a lot of unpredictable ways, it makes more sense for passive income to just ride the market by investing in a Total Domestic Stock Market, Total Bond Market, and Total International index funds, with allocations that depend on your goals and time horizon. For income, withdraw 4% or less, depending on what research you believe, and you’ve got a pretty low risk strategy.
Though it can take a while to build up enough cash to put a 20% down payment on an investment property (the typical lender minimum), they can snowball fairly quickly. The key here is to correctly project income and expenses in order to calculate cash flow (the free cash you can put in your pocket after all associated property expenses have been paid). However you have to be sure to include the cost of a property manager in your calculations unless you want to manage the property yourself. Even with a property manager, you may be required to make large repair decisions every now and then – so while this is not a 100% passive activity, you are not directly trading your time for money like traditional employment.
For those of you who don’t want to come up with a $220,000 downpayment and a $900,000 mortgage to buy the median home in SF or NYC, who don’t want to deal with tenants or remodeling, and who wants to not do any work after the investment is made, check out Fundrise. They are my favorite real estate crowdsourcing company founded in 2012 and based in Washington DC. They are pioneers in the eREIT product offering and they’re raising an Opportunity Fund to take advantage of new tax favorable laws.
With $200,000 a year in passive income, I would have enough income to provide for a family of up to four in San Francisco, given we bought a modest home in 2014. Now that we have a son, I'm happy to say that $200,000 indeed does seem like enough, especially if we can win the public-school lottery to avoid paying $20,000 to $50,000 a year in private-school tuition.
As doctors, we most likely fall into the first category. We may be rich in the sense that our salaries are in the higher economic range, however, because of our expenses (houses, cars, student loan debt, private school tuition, practice overhead, etc.) and sometimes poor decisions, we have a tough time accumulating any real wealth. We’re also handicapped by the fact that we start along this financial journey relatively later in life.
There are three main categories of income: active income, passive income and portfolio income. Passive income has been a relatively loosely used term in recent years. Colloquially, it’s been used to define money being earned regularly with little or no effort on the part of the person receiving it. Popular types of passive income include real estate, peer-to-peer (P2P) lending and dividend stocks. Proponents of earning passive income tend to be boosters of a work-from-home and be-your-own-boss professional lifestyle. The type of earnings people usually associate with this are gains on stocks, interest, retirement pay, lottery winnings, online work and capital gains. 

Finally, in the world of finance, residual income is a method for valuating a company, based on the net income it has left, once it has paid out equity charges to its shareholders, to compensate for their investment risk. To understand this absolute valuation method, check out the formulas below. Though they don’t directly fall under the scope of our endeavors, it’s important to understand that residual income can be a powerful asset in the eyes of potential investors into a business enterprise.

Residual income is the best model for money generation. Once you master and build up one avenue, you can devote your time and money into another avenue. Eventually you start reaping the benefits of multiple residual income avenues. Enabling you to have complete financial and time freedom. I recommend to all people to build these types of asset models as they can greatly improve their life.