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.

Rehab must cost more than the purchase of the building.This was a layman's interpretation of the actual rule which is:The qualified rehabilitation expenditures exceed the greater ofThe adjusted basis of the building (and its structural components), or$5,0002.

It's also wise to budget for unexpected repairs or delays.

But you are correct, often seller fi is a component of the financing.  

Whether you are a startup, you have started and ready to scale or you are nearing Cardone's level you need to look at 4 components and how you build the processes and systems. 1.

Plus, it gives me peace of mind knowing that I have a buffer for unexpected repairs.

This is an often overlooked component.

The Brrr strategy works best with a value add component that forces appreciation. 

If you something unexpected pops up you lose money on the deal.

With the potential rental income versus your mortgage and expenses, breaking even or making $200 a month doesn't leave much room for unexpected costs or vacancies.