It was ground down 3 inches and we added 4 new inches of pavement, rolling the pavement, etc. 

Today's asphalt roofs typically last 15-25 years. 

Side note: there is no asphalt paving through the property.

Presidential Shake ® Shingles - CertainTeedhttps://www.certainteed.com/residential-roofing/products/presidential-shake/Asphalt Shingle Limited Warranty

New work includes all new plumbing, energy star rated windows, dimensional asphalt roof, LED lighting 2 renovated full bathrooms, chefs kitchen, gas fireplace, and 200 AMP electrical panel and new distribution wiring.

They are typically a bit more expensive up here than asphalt shingles but have a longer life span.

A lot of profit killing mistakes are missing big items in your scope of work (plumbing, sewer, electrical, hvac, roofing, siding, pavement/concrete, foundation, termites/mold, etc.).

Only updates made included changing roof (flat asphalt), paint rooms, and make minor repairs.

@Kevin SederLocal brokers and pounding pavement will get you best leadsBP I use for education

It's like you're saying but a bit more complicated.True, there are components of the property that depreciate over a faster life5-year = Personal property (furniture, fixtures, carpeting, appliances, etc.)15 year + Land improvements (landscaping, pavement, fencing, etc.)BUT, according to the IRS it should be done through a quality engineering based study, otherwise known as cost segregation.