The life of your filter depends on your environment and the type of filter you have installed. To put it simply, there really is no concrete answer to this question. Certain things such as:
- The number of people who live in your home
- If there are pets in the house
- If there is a smoker in the house
- If you leave the windows open
- If you have pollen bearing trees or plants in the neighborhood
- If you live in an area with a lot of dampness
- If you live in an area that is dry or arid
- Plus many others...
If several of these factors sound familiar, you'll likely experience a quicker loading of particles on your filters and will consequently have to change it more often. A good rule of thumb is to check your filter every month. If you can hold the filter up to a light and not see through it, it is time to change your filter. At an absolute minimum, you should change your filter every three months. A clean air filter will also prevent dust and dirt from building up in the system, which could lead to expensive maintenance and utility bills.