Capital Expense Total Replacement Cost Lifespan (years) Cost per Year Cost per Month Shingle Roof $5,000 15 $333 $27.75 Metal Roof $13,200 36 $366 $30.50 Water Heater $1,200 3 $120 $10.00 All Appliances $2,000 10 $200 $16.67 Driveway/Parking Lot $100 1 $100 $8.33 HVAC $3,000 10 $150 $12.50 Split HVAC $3,000 4 $750 $62.50 Flooring $2,000 6 $333 $27.75 Plumbing $3,000 15 $200 $16.67 Windows $5,000 10 $500 $41.67 Paint $2,500 5 $500 $41.67 Cabinets/Counters $3,000 10 $300 $25.00 Structure (foundation, framing) $10,000 30 $333 $27.75 Septic System $2,500 24 $104 8.67 Components (garage door, etc

My job has about 21 square of shingles and also a flat rubber roof on a porch. 

You have a few different materials used in that foundation, i agree with @Russell Brazil on this, yes there seems to be some " handyman" work done, but nothing bad enough that can not be fixed with some jacking up and repairing certain areas. the contractor probably does not want to bother with it ( who knows, he may want the property himself after seeing it) so he is trying to make you think there is a ton of work to either give you a high price or hopes you will walk away so he can grab it. the roof, plan on installing a new roof, shingles look close to their life span and not because of the color, look at the gaps between each tab ( the views from above show it best) when they start to widen up that means the shingle is drying up and close to the end of it's useful life.

The roof is 10 years old shingle.

If so, were permits pulled & were they installed by a professionalAre any of the homes rented to studentsIs there a flat roofare there asbestos shingles The Year that the following were updated (either partially or fully) would be good to know:- Heating systems- Roof- Plumbing- electricalSome companies will not write properties with systems that have not been updated.As long as you are living there, the proper policy for a 1-4 family is a "Homeowners" policy.

If you are not familiar with roofing you can easily be taken advantage of...15 yr shingles, no underlay, no ice guard, old shingles not removed, chip board sheathing material etc. 

Are they low-grade shingles or better quality architectural shingles?

The shingles look like they are in good condition, but the flashing and the gutters definitely need some work.  

Asphalt shingle roof for a house that size is about $6,000.

The house presently has 2 layers of shingles and there is a leak over the bathroom.