.* Appraisers with lack of skill or motivation (due to their low fees received or charged) which deters them from doing the work required for an reliable valuation.* Residential properties (2-4 units) are mainly valued by sold comps and not with the income approach, since these properties are typically not purchased for their income potential exclusively.* adu/jadu's add contributory value to the property as a whole, which may or may not = the cost to build them.

I just want to offer what estimating skills I have, since BP has helped educate me. 

The variables are skills, confidence, and love of the game.

Also, it is a great way to learn many real estate skills while maintaining a roof over your head haha. 

Marketing only on Zillow is amateurish, which indicates they may be lacking skills in other areas.If your unit rents for $1,000 a month, you are losing more than that because of utilities.

That means their due diligence skills aren't very strong.

You could also get a Full-Time or Part-Time job in any part of real estate....working for a top Real Estate office on weeknights and weekends, working for an RE Investor, working for a General Contractor and learning a few skills, etc.

Trim, doors cabinets etc. we usually spray - but those can be brushed and look professional if the painter is skilled.  

They recruit, interview, check references, skills test, criminal background check and drug test. 

They bring in the experts in a specific area vs the GC who may not be certified/skilled in the area e.g., mold remediation, asbestos removal, etc.The point you're making is what I'm leaning towards.