How often should I change my CPAP filter, considering the various factors that could influence its longevity? Is it necessary to adhere to a specific timeline based solely on the manufacturer’s recommendations, or should personal circumstances, such as environmental conditions and usage frequency, play a pivotal role in determining the appropriate replacement schedule? For instance, if I reside in an area with high levels of dust or allergens, might my filter require more frequent changes to ensure optimal performance? Additionally, can the material of the filter—whether reusable or disposable—affect the frequency with which I should undertake replacements? Moreover, is there a tangible difference in air quality or machine efficiency when using a fresh filter compared to a worn one? What are the signs that indicate it might be time for a change, and should I consider any preventative measures to prolong the filter’s effectiveness while ensuring my CPAP machine operates at its best?