Product review (5 stars): Keep Your Water Supply Safe!
I think this is the best way to stay ahead of a supply of these filters.  I've been very diligent about keeping at least one on hand by ordering just as soon as I use my last one.  Every 6 months to keep the water supply good for drinking and for ice.  These have been much better than the after-market ones I tried.  (Those leaked something awful!)

Recommended.  Both for quality and for price.  (Much better than my local big box hardware store!!)