Product review (5 stars): Great filters but 12 months is a stretch.
I just ordered my second set and noticed that they say "double lifetime should last 12 months".  I think if that is your expectation than you might be disappointed.  I change mine when the flow when filling up my water starts to noticeably slow, about 4-5 months.  Water is different all over the country, my TDS is about 220 which is a little hard.  I love these filters and would never expect for a second to get more than 6 months out of ANY filter even the Samsung at my house.  The water taste good even right before I change them out., I still like and would recommend these filters. 3 lasted me 15 months.