The answer to 'why is my ridge vent worn out' is that ridge vents typically have a lifespan of 10-20 years, and can become worn out over time due to exposure to the elements. Common causes include UV damage from sunlight, deterioration of the vent materials, and damage from high winds or severe weather.
Symptoms of a worn out ridge vent may include cracking, warping, or gaps that allow air and water leaks. In some cases, the vent may become dislodged or detached from the roof. If your ridge vent is showing signs of wear, it's important to address the issue promptly to prevent further damage to your roof.