I had nails put in the wrong place on a roof on a home I purchased . It eventually caused problems . A roof that should have lasted 30 years only lasted 18
One leak I had ruined the ceiling sheet rock and the sheathing rotted. A leak in a roof causes major damage, and it takes a long time for the homeowner to know it is leaking. The water has to soak the insulation and then penetrate the paint before it shows itself. By then the damage is done. And ranches have such a low attic that it is impractical to go up and check every time it rains.