I did find their business model pretty fascinating and can see investor application to it as well as obtaining listings for SFH.  

This is where some art more than science can come into play.

@Harrison Liu This is not a perfect science, but you realized you "lost" $21,600 ($150 lost rent X 12 months X 12 years = $21,600) over the years.

I find this site addicting and fascinating.

This can be as much art as science, but the guiding principals are to compare like to like, within a short radius to the subject property, around the same size, same number of bedrooms, bathrooms, same type of property, similar condition, etc.

Quote from @Patrick Buntubwimana: The 50% rule, 1% rule, 2% rule, or any other "rule" is not a fixed science.

Apartment investing is not rocket science, and it is a learned skill just like any other.You need to select a market to invest and begin to build out your team members, especially brokers.The fact that you have a stable financial situation is key when you start.  

It's definitely not impossible, it almost feels like studying Computer Science.

Cheaper than a garage.One thing that fascinates me is that some tenants view late fees as a blessing. 

I am fascinated by the concept of multi-family investing.