Land in michigan is less than in texas , north texas.I will give you examples on cost differences.Material prices are the exact same price if not a little less.texas framing price per sqft $2.00plumbing $9500hvac $9500concrete Labor only $2.00 per sqft  Concrete $180yd 5 sackdrywall $10500Electric $8000Ok here are the michigan prices , better sit down.framing $13.00 sqftplumbing $25,000hvac  $20,000concrete is about the same for materialdrywall $20000electric $25000Both quotes were for a 3/2/2 home with 6/12 roof hipPeople in michigan wonder why houses are so expensive , its because of the sub contractors.The plumber only has about $5000 worth of material to do a whole house but yet there still asking for $25000

If there is a leak, the first thing that should be done is to cut a hole in the drywall or plywood to get the wet materials out. 

Is there more reading material regarding this aspect ?

I'm not thrilled with work I've seen but I think that is b/c the homeowners chose cheap materials.3.

Materials have to be stored somewhere , usually the last room to be done . 

.$30/board should cover all labor and all materials...

Regarding downsides, or perhaps good barriers to entry, saturation is pretty strong, good help is quite hard to come by, inventory has been hovering around 25 or so homes for a while (most of which are not STR material), and much of the recent cabin listings have been grossly overpriced.

When I do, I use a written agreement that explains specifically what they will do, who pays for what, the materials to be used, a completion date, etc.

This includes construction, materials, labor, permits, and any other associated costs.Negotiate TI Allowance:Landlord and tenant negotiate the TI allowance amount based on the estimated total cost of improvements.

As you have experienced, trying to predict what will happen through the course of two years is very difficult - contractor integrity, materials costs, what the sale price will be, what the rental price will be.