These methods include: Detailed Engineering Cost ApproachDetailed Engineering Cost Estimate ApproachSurvey or Letter ApproachResidual Estimation ApproachSampling or Modeling ApproachExperience or “Rule of Thumb” ApproachIt’s important to understand the differences between the approaches including which one best fits your property and the reliability of each approach.DETAILED ENGINEERING COST APPROACHThis approach compiles the costs from construction and accounting reports to build a report.

To save those costs, you might want to stick to some year build and older, for example, if you cannot do inspections on the properties that you are buying due to off-market deals or something else that is hindering you (all sellers I buy from do not want anyone in the home till we close).

Hey @Dalton Foote - I highly suggest  using a renovation loan and house hacking a multi-family if that is possible with your current life circumstances.The 203k and homestyle renovation loans are just amazing products and drastically help you reduce your risk, in my opinion, because you are able to leverage the cost of the entire renovation with such a low down payment loan.We work with a lot of clients who use these products in Chicago, and no matter what, in the long term, they gain great equity.If you aren't able to house hack - the process is essentially the same, but just with more money down with hard money or conventional construction loan.

If you find someone that will let you supply the materials and work for labor only and sign a contract you supplied , you have hired an employee , a laborer , not a contractor .

I lived well below my means, worked a full time job for years while doing this on the side, persisted when others did not... and now I am enjoying the fruits of my labor.  

Would the person who takes on more labor to repair the property have greater preferred equity or is this usually treated differently?

During my REI investing journey I've done 7 1031’s, then followed each of these up with cost segregation studies.

However, I still struggle to understand the art of estimating rehab costs. 

For residential multifamily properties (1 - 4 units), can you use a home warranty to take care of the repair costs associated with rentals?

Turning over some kind of commercial property is more labor intensive but it also scales quickly because of potential returns.