All expenses meaning the usual taxes , insurance . also including  any repairs ( in 2020 we averaged $46/ month / door for repairs ) which may seem low but keep in mind when we rehabbed we replaced - repaired all major components if they were more than 5-10 years old depending on the component.

The main thing is just differentiating the 1%ers that appear nice but have issues from the ones that have had their major components (electric/plumbing/hvac/roof) updated more recently.

@Eric Hemplershort answer - I don't think you're overlooking anything, and this is what I am seeing as well.I think it's a combination of all of the economic factors: a shortage of houses in desirable markets + pressure from home buyers + investors willing to settle for lower returns + low(er) interest rates - and probably othersseveral options as others have pointed out:-accept the lower returns-find something off market and/or with a value add component rather than a plain jane MLS listing-don't invest in RE

@Charles McCabe 1-4 units is only residential if it does not have an office component. 1-4 + 1 office is considered mixed use COMMERCIAL. let me know if you have any questions, my DM is always open :)

I wish there was a tool which can look into age/condition of the house, locality, demographics etc. and predict all the cost components such as vacancy, maintenance with a high confidence.

This is a great component that speaks to my wanting to streamline my investing strategies and overall path. 

Secondarily, rents are only one component of the purchase.

Once I have the property under contract I will have an inspection completed to identify any deficiencies and determine the useful life expectancy of major components/appliances.  

Edit....Nicholas Preston forgot and incorrectly did not add other important components in the formula.

Purchase price: $620,000 Cash invested: $72,000 $30k reno on an acquisition we created our own comp on by selling the home next door at $702k.