One opinion out of many... Leverage your investments and spread it out over several. That may actually be safer than having just one when you consider vacancy and repairs.

Hypothetical example.
100,000 property, 12,000 annual rent, 4,500 operating expenses (property tax, insurance, repairs, replacement reserves, vacancy cost, management fees, etc.) 7,500 profit = 7500 in cash flow, potentially 3% increase in value based on historical inflation rates yields another 3,000 of capital gains.

net profit plus appreciation = 10,500

100,000 invested in 4 properties at 75% LTV 5% interest 30yrs
48,000 annual rent, 18,000 operating expenses, 30,000 gross profit, 19,500 debt service, 10,500 cash flow and 4,500 of principle reduction (15,000 profit), potentially 12,000 of capital gains based on 3% inflation.

net profit plus appreciation = 27,000

Second year all cash (3% inflation), rent increases 360, expenses increase 135, cash flow increases 225, potential 3,000 appreciation.

Second year leveraged, rent increases 1440, expenses increase 540, cash flow increases 900, potential for 12,000 appreciation.

If you have a vacancy with one property, your income drops to 0, vs 75% if you have four properties.

Bottom line, if you can get a 7.5% return and borrow money at 5%, you are making a 2.5% spread. When you add in appreciation for historical inflation, the leverage boosts that portion of the return from 3% to 12%. It is a little more work with more properties, but not 4x the work, especially with a good team in place.

DYODD, returns are hypothetical, seek your own legal and financial advice, etc...