Refrigerator water filters

I am in the market for a new refrigerator, my old one - though still going strong - is now 24 years old !

I notice that many of the new refrigerators have built in water filters. How good are these filters (I am looking at a Kenmore refrigerator)? Should I consider a separate water filter before connecting the icemaker pipe to my water supply or will the built in refrigerator water filter be adequate? What are the recommendations?

Thanks.

filter

The replacement cartridges are expensive, but they are more convenient to replace than pulling the refrigerator out to change an outside one. Since they are somewhat small their capacity before changing is less also.