Starfish Food

Does anyone out there know how often the refrigerator water filter should be replaced? I have a Whirlpool refrigerator. I haven’t had any obvious signs yet that the filter needs to be replaced, but I’m drinking the water so often that I thought it a good idea to check before things start to go bad. The last thing I want to do is take a gulp of something that does not taste clean. I’m interested in information about part #4392857. I’m sure there must be some general rule of thumb and would appreciate any help someone out there might be able to provide.