Refrigerator water filter replacement intervals vary among the different manufacturers. Whirlpool's water filter # 439608 is the most common water filter by Whirlpool and replacement is recommended after six months or 400 gallons of usage.
The 4396508 filter is easy to replace, just follow the instructions on the filter itself or on the package the filter came in.
For more information on water filters visit us at www.myapplianceparts.com