In our area, the housing authority does annual inspections to (mostly making sure the landlord is keeping up the units) review the tenant and the landlord. 

This contractor has 0 reviews on yelp which I found a bit sketchy, but was able to vet him by his contractor's license, worker's comp, and by visiting some of his ongoing projects.

With Google, Yelp, Facebook reviews as well as what is on their site and what type of content they are posting on their social media pages....

After reviewing your application, we’ve determined that, unfortunately, we are unable to move forward with your application at this time, as it does not meet our established criteria for income and (other established criteria) We appreciate the time you took to apply and wish you the best of luck in your continued search for a home. 

Quote from @Jed Butikofer: Quote from @Jonathan Greene:If you aren't house hacking, multifamily deals should be profitable (maybe not in CA).When I review markets I have lived in, I see 2 bed duplexes for $500k-$700k while only generating $1,400 each in monthly rent.

As a licensed contractor and real estate agent, I can review your estimates, ask the questions you might not know to ask, and help you make an informed decision that balances cost with quality.

I get the frustrations of laundry and especially losing expensive luxury linens that gain 5-star reviews and very happy guests.

Lots of other services are included at no cost (advice, doc review, debt collection letters, etc). 

Even if the HOA currently allows rentals, it’s worth attending HOA meetings or reviewing their amendment history.

An attorney can help review contracts, especially if private funds or partnerships are involved.You’ve got this—good luck with your first flip!