First of all - most people (including real estate investors) are lazy and will always gravitate towards promises of quick returns / passive income promises.But also - what you are describing is something that AirDNA does extremely well and automated - it can be a little pricy, but way way more effective and accurate to do this with that tool - highly recommended

Guys with problems end up gambling everything away because they've lost too much to walk away now.

They may be more or less accurate depending on the specific analysis / specific property.For a house hack, you generally want to look at your expenses both while you're living there and when you move out.  

@Gino Barbaro @Charles Seaman are both accurate.

Do you use any other data sights that might help determining accurate numbers? 

Single boiler serving a duplex- landlord paid water / natural gas because there's no way to split it accurately. 

Seller shall provide such documents and information, representing them to be true and accurate, within _______calendar days after acceptance.

About as accurate as CarFax.  

BP rent estimator has been rather accurate in my searches.  

To get accurate information on renting by the room, check with a local investor-friendly real estate agent.