Someone else mows your lawn, fixes or replaces your appliances, removes snow, takes care of the roof, fixes plumbing and electrical issues, the list goes on. 

The roof is in good shape.

-does that say the roof is 20 yrs old?

Inspection came back and I estimate $15k repairs (which includes $5k for two trees to be removed hanging over the roof, and $5k for a back deck that is wood leading to concrete stairs - terrible construction).

IE. heating system, roof, windows?

New roof?

Simple example: if you need a new roof in 10 years and you know it will be 10k, you know you need to set aside 1,000 per year.

The house is almost finished but won’t qualify for FHA or VA financing due to it still needs a roof.

Framing, roofs, exterior, plumbing, electric, ect. 

I own an older house that's in decent shape but needs some renovations including adding dormer to our attic (or just raise the entire roof possibly depending on expense) to facilitate a closet and more headroom creating an actual bedroom.