I don't think there is a clear cut answer as each has pros & cons.Both SFH or MFH have issues and typically MFH cash flow better.

I have made 60,000 commission before on a 40 cent mailer to an apartment owner.Targeted and a laser focus list of properties with specific buyers for that size and range tends to work best.

You want to move up the 80/20 leverage curve from technician to investor/entrepreneur.In Bridgeport, CT and New Jersey the investment is about 10% of rents collected which frees you from taking resident phone calls, coordinating maintenance, leasing vacancies, accounting P&L's, conducting inspections and making property payments.Owners often times suffer from "death by 100 cuts" when having to handle all of these small items, missing opportunities to achieve bigger goals.

Members of that organization tend to (though not always) be a cut above the rest.

“A river cuts through rock, not because of its power, but because of its persistence.”James Watkins

I don't want to cut out money, but I want to be smart.

Many parents are worried that additional cuts to teachers are on the horizon unless CPS gets bailed out by the State this month. 

At that point, I would look to just cut back to working 2 days per week.

Assuming the same rates, it will take me another 9 after that to go from $200k to $400.Most of the books out there seem to suggest that with leverage you could make about 12% per year, which cuts down the number of years substantially.

Best way is to obtain authorizations for release of credit, tax returns, assets and liabilities, then send copies or get several originals to use, mail them  and obtain information directly from the source, this cuts out the chance of fraudulent statements.You also need to underwrite the type of business, what hazards are present, toxics, fire, insurance coverage, competition with other tenants, traffic counts, environmental laws applicable to them as well as your infrastructure being sufficient for tha use.....electrical, plumbing, traps, fire codes, etc.