Hvac, roof, plumbing, appliances, etc. 

Another benefit is the ability to dispose of a component like the old roof when a new roof is installed. 

Most times, the due diligence period is used for you to bring out your inspector to physically test the property (environmental, structural, roof, etc.) 

Everybody thinks they understand real estate, after all its just walls and a roof?  

So I’m in a bit of a bind, I have a duplex I’m house hacking we remodeled entire thing, new hvac, electric panels, electric main, updated plumbing, water heaters, furnace, install central air, roof.

a lot of new investors run rosy numbers, see that they'll get $250 a month in "cash flow," and then they have to replace a furnace (in a single family) or a huge roof (in a multifamily) and that "cash flow" is gone for years. 

Have the opportunity to purchase 64 homes, all have renters, book of business is very profitable. 90% of the properties have new roofs.

Roof, HVAC and foundation all have no issues.My plan with a property like this would be to get positive equity asap and re-fi.

Will you be required to inject capital if they need it to repair roofs / foundations / plumbing / etc. 

You want every single nook and cranny of the basement, as much of the roof line as can be seen, the entire property lines and grounds, the road in front and neighboring 8 houses.