Inflation is constantly eroding buying power; each year, it costs more to buy the same set of goods.

I’m really looking forward to that project getting completed. as for my renovations we did everything: (for my both the main home and ADU) Roof, siding, electrical, plumbing, floors, etc.

events happen and you need to evacuate or there's extended duration power outage and no AC, food, etc for the facility.   

I have bids to tie in plumbing and electric to make a second set of hookups.

Purchase price: $70,000 Cash invested: $80,000 4/1 converting to 3/2Full RehabUpgraded electricity, plumbing, added HVAC, new roof, all new walls, sub floor, flooring, opened up living/dining/kitchen into one large area ...

You need to make more than that to just keep the current buying power of your Dollars without any Profit after Taxes.

Knowledge is power and business is about knowing more than the next person and putting that knowledge into action.  

No doubt a good deal and house hacking a duplex is powerful for building your wealth.

Electric.

You will also likely need street/sidewalk closure permits at different points in the jobUtility Taps- Water, Sprinkler, Sewer, Power, Gas, Cable (this is likely negligible as the cable company should do it for you)Excavation/Foundation- Are there buildings on either side?