There are many good reasons to perform a close inspection of an attic. An inspection 
might reveal stress cracks that could lead to future problems. A close look inside gives the buyer peace of mind that the size of the lumber is correct and up to code. An inspector will look at the type of insulation in place, whether it was installed correctly, and if it is adequate for the home. A major concern is leaks. Your home inspector will check for water stains, rot, and any other signs that water is coming in through the roof. Additionally, the inspection will include looking for evidence of animals in the attic. Squirrels and other small animals can cause damage to wiring, insulation, and more. If the house has a chimney, it will be inspected to determine how structurally sound it is.
In the photo, you will see an example of American ingenuity at its best! Where there once was a roof leak there is now a water reclamation system! Of course, this problem was corrected right away!