It is very important to replace your air or water filters because a dirty filter does much harm than providing filtered air or water. If you are using water filters in your homes it is advisable to replace your filter cartridge every three months. Since there are many types of water filters like pool filters, pond filters, shower filters, whole house water filters etc. there is no rigid rule to change the filter but it is advisable to change/clean the water filter every 3 to 6 months.
If you are using permanent air filters it is required to clean the filters every 30 to 60 days depending on use. Disposable air filter users can replace filter pads every 3 months depending on usage. Basically, don't wait for the entire filter to become matted with dust. If most strands of fiberglass like filters are coated with dust, it's times to replace it. Also, some filters clog more quickly than others.
