Hi, I am the owner of DealMachine.

For example in many jurisdictions I can STR units in a duplex but cannot STR an ADU (some jurisdictions will let you STR if you owner occupy).

The first apartments I rented as the owner, were previously rented by the former owner at $150 month including utilities. 

You'll be competing on price with owner occupants who are not running the arithmetic like an investor, so you'll often end up overpaying and losing out on any potential cashflow.I'm also 25, and it's great to see other young guys getting started and building wealth. 

I have seen a post from a guy that broke down his criteria for properties above 200k and below 200k and the price he is willing to pay for "deals" is so low the owners would be practically giving them away like buying an owner out saving them from a foreclosure and his comp forcast is for a 1 mile radius not 5 or 10.

You paid the property owner $40,000 in rent.  

I have used owner finance and hard money mostly to build my portfolio but need some institutional refi in the future.I'm also thinking about how this affects taxes, insurance.Thanks in advance for sharing your opinions!

@Rafael Valdor some advice when screening PMCs-----------------------------------------------------------------------------------------------------Recommend exploring as many sources as possible to get referrals AND cross-reference them to get as much accurate information as possible.Check out NARPM.com, BP’s Property Manager Finder (BiggerPockets: The Real Estate Investing Social Network), etc.Also, encourage you to learn from the mistakes of others - by reading posts here on BiggerPockets about owners not having their expectations met by their current Property Management Company.

Possible to maybe build one similar to this with an add on for small business owners and REI's. https://docs.google.com/spreadsheets/d/1xYOKT2eNS588cj6_8jVv2vobAfAhCVUd/htmlview#gid=1221524195

They might refuse since you are not the owner.