Assuming you sold the home at the end of 5 yearsYour NET ROI would be:0% appreciation: 10.93%1% appreciation: 12.13%2% appreciation: 13.33%3% appreciation: 14.53%This ROI calculation takes into account taxes, insurance, selling costs, repairs (calculated at $3500) through out the lease.

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?

You also have to ask about delivery costs and more.LABORLabor charges are trickier to understand, but Google AI to the rescue! 

Building a 4,000-square-foot, three-story duplex with a 1,000-square-foot ADU could cost about $1.83 million, including construction and permits (excluding land).

It's probably best to have them pay out of pocket for a smaller cost like this.

Purchase price: $15,000 Cash invested: $25,000 Sub to deal - paid the seller and wholesaler $15,000 + $7500 closing costs to assume $84,000 mortgage with a monthly PITI of $575.

Given that the property was worth $390K in its current condition, I saw an opportunity to make the numbers work while keeping my upfront costs low.Instead of increasing my cash offer, I negotiated a $25K down payment with the seller carrying the balance for two years through owner financing.

It did not cost me $0.01.  

While it will not reduce the actual cost it will help with the monthly cash flow.I am curious if this was a single-family house converted into a double.