MAC cannot guarantee a brush for life. This is largely in part due to the fact that most (not most of us here,though) brush consumers do not bother to take care of their brushes. Taking care of your brushes includes washing them at least every 2 weeks or so (depending on use), not getting anything past the ferrule wet, and using Brush Cleanser to wash them (Zest, Lever 2000, Lava, etc are not appropriate stand-ins for Brush Cleanser). I think when rumors such as these get started is when MAC customers take advantage of MAC's very generous return policy. Now, of course, if something is defective with your brush (i.e. the head falls off the second day you own it, then yes, MAC should and gladly will replace it), but when people who have owned their brushes for many years try to exchange a brush because it is falling apart from their own misuse can be very frustrating. For the record, MAC cannot guarantee any brush because they can't be sure of how you're taking care of it once you leave the store. If customers continually misuse the MAC policy I can almost assure everyone that MAC will change it to be more rigid and less liberal. I believe that most of us on this forum are grateful for MAC's policies and would be respectful consumers.