A roof ventilation system needs replacement and restoration from time to time, much as every other building. The value of repairs, of course, can be overlooked, but ultimately, this can lead to far more severe issues than just air stagnation. For example, a device that has not suffered for years from the replacement of vents and turbines will collect unsafe and dangerous substances. If the contaminations are not cleaned away timely, the vent could poison the air in the whole house.