100% Vacancy vs 50% vacancy

Two (or 3 or 4) are better than one!
When you're buying investment property look for buildings that have more than one space to rent out.

Rather than a single family house where you have to pay 100% of the mortgage payment if it is vacant; buy a unit where there is a basement suite as well. That way if one suite is empty you only have to pay a portion of the payment.

I once bought a fourplex and with the cash flow I could have one unit empty at all times and still make the payment. It made for a low stress purchase.

So keep your eyes open for units with extra space to rent out. A suited house with a garage is even better because it has 3 parts (the upstairs, the downstairs, and the garage) from which you could earn income.