I should also mention that despite owning multiple properties with very little leverage on them, real estate isn't my biggest holding.  

^^^Biggest driver of wealth in real estate is the long-term appreciation, especially in Denver.

I'd say my biggest mistake was not researching the property manager properly before hiring them.

Just to add mate, the biggest and best turnkey providers even sold for above fair market value.But the market was moving so much that in short time the property was worth more.Looking back, we should have done the same but I didn't believe Toledo would catch up so quickly.Which it did.I laugh now at what prices we sold some properties for.It is what it is...

Biggest dig: no accounting functions. 

you left out the biggest factor which is risk.

The biggest takeaway is learning the process and what steps you need to take to complete the purchase. 

Personally, I'd never buy the biggest house, or the most expensive house on the street.

There's so much medical traffic in Oklahoma City with the biggest and best hospital in the state.

Biggest thing to me is why wasn't the first round of capital enough, and why wasn't it brought up to 90% Occupancy ages ago?