Short Answer
Homeowners should generally avoid unnecessary roof access because of safety risks and the possibility of damaging roofing materials.
Detailed Explanation
Walking on a roof is dangerous — falls from roofs cause serious injuries and deaths every year. Beyond the safety risk, walking on a roof can damage the roofing materials: shingles can crack underfoot, especially in cold weather when they're brittle; granules can be knocked off, reducing shingle life; and the seal between shingles can be broken, making them susceptible to wind damage. For these reasons, homeowners should generally avoid walking on their roof. Visual inspections from the ground, from a ladder at the eave, or from a window can identify many problems without the risk. For a thorough inspection, hire a professional who has the safety equipment, training, and experience to access the roof safely without damaging it.
Why It Matters
Walking on a roof risks personal injury and roof damage. Professional inspections are safer and more thorough than DIY roof access.