Rheem specifications call for cleaning or changing the filters in air conditioning units on a regular basis, every two or three months. Cleaning or replacement options depend on the condition of the filter, how much use the unit is under and if pets are present in the environment.
Clogged filters reduce the efficiency of the unit, increase the cost to operate it and shorten the lifespan of the equipment due to being over-worked. Pet hair can significantly reduce the life of the filter. A home's heating and cooling system is expensive to replace and regular filter changes are a relatively inexpensive maintenance precaution.