The neighbor might be the biggest burglar in the town for all I know.

My biggest regret is not signing up to get locked into 20% off annually.

The biggest red flag is that the potential tenant isn't even good at potential fraud.Do a thorough background check to make sure they're not just giving you some nonsense or friends to pretend they're employed. 

My biggest issue with snowballing is my family's budget must be paid by a decent percentage of the income I make

My biggest advice would be to take your time and do as much research as possible.

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.