They are also simpler over the life of the unit to maintain because there are just three main components instead of four(+) with HVAC.  

For newly constructed, purchased or renovated properties and also retroactive generally over the last 10 years, building components are properly classified into individual units of property and accurate recovery periods for computing depreciation deductions.

If you go with a self-directed Solo 401k plan, you can supercharge its Roth component by investing in illiquid assets such as trust deeds and converting them to Roth at a deep discount.

I think you're recommending a more detailed analysis involving the age/condition of all the building components/systems and prorating those costs out over time.

All of the components of construction, I left off land.  

Regardless of how real estate -ish we are here, there is a huuuuge technology component here, too.

For newly constructed, purchased or renovated properties and also retroactive generally over the last 10 years, building components are properly classified into individual units of property and accurate recovery periods for computing depreciation deductions.

The categories match up pretty well with the 25 components I call out in my Estimating Rehabs books.Btw, this is the way my accountant recommended I set up QB...he's the one who moves everything to WIP at the end of the year for the properties that haven't yet sold. 

Boxabl acknowledges SEC inquiry in updated filing | Business Insider India its a double whammy start up and trying to sell in a very tough interest rate environment. along with inflation and cost of components to the point their 50k to 60k box probably cost them quite a bit more to produce than what they were going to sell it for. 

I was just into about my 20th new build in a 90 home project when this happened to us.. lumber packages did not quite 3X but they certianly went up 2X along with a host of other components.. the one benefit we had was we could have lumber escalation clauses in our contracts that passed this on to the buyer..