Keeping units serviced with high-performance chemisorbant media is a very important part of system maintenance. If the media is not changed out when it is due for replacement, the unit will not function properly and unwanted gases will be released into the environment. The life span of media will vary depending on many factors, such as type and quantity of gas, airflow, etc., but on average it lasts for a little more than a year. There are multiple ways to test and see if the media is reaching its expiration date.