This is the 3rd replacement cartridge I have purchased from a big box that reps Delta.  The other two lasted 2 years and 2 years 7 months.  The problem is they just don't turn off when placed in the off position.  Have to play with the lever to insure it doesn't leak, drip or stream.  It is just my wife and I in the house no kids that are hard on the lever.  As I read through the reviews this is a consistent problem that has not improved.  I understand planned obsolescence & selling high profit parts but I can't believe DELTA brand is pleased with this poor quality part tarnishing their reputation.  Product sheet lists lifetime warranty but this part is the critical path item and should last longer than a couple years.