Product review (5 stars): Use these top quality cartridges BUT you may not need to replace as often as recommended
You just can't go wrong buying original manufacturer GE refrigerator water purification cartridges actually made by GE.  Since they're fully enclosed (and consequently you will never know exactly what's inside) you should be able to trust the original manufacturer, who has a reason to make high quality replacement parts so that you don't think your fridge is defective.  On the other hand, refrigerator owners need to know that your GE fridge is programmed to notify you to replace the cartridges every six months WHETHER OR NOT you need to do so.  We've easily gotten more than a year out of each cartridge; you can tell it needs replacement when the water doesn't taste quite as fresh as it should.  I like to keep an extra cartridge on hand in case I need one quickly, but so far that has never happened.  Happy Hint:  Write the date you replace the cartridge on the cartridge itself with a black sharpie pen, and that way you will know exactly how long your cartridge lasts (which can vary according to the water supply you are using).