The answer to 'why is my shingles worn out' is that shingles typically wear out over time due to a combination of environmental factors and normal wear and tear. Common causes include exposure to sunlight, wind, rain, and temperature changes, as well as improper installation or maintenance.
Some common symptoms of worn-out shingles include curling, cracking, blistering, or missing granules. If left unaddressed, worn shingles can lead to leaks, water damage, and other serious issues. In most cases, it's best to have a professional roofing technician inspect the roof and recommend the best course of action, whether that's a partial roof repair or a full roof replacement.