Keep in mind I'm talking about your average home-owner. Someone who takes COMPLETE proper care of their knives (i.e. a professional cook) will definitely get more use out of their knives. There is a huge difference though between the way a cook takes care of their cutlery and the way your typical home-owner does. Henckels used by a cook will most certainly last more than 4 years before needing to be replaced, but someone who is not well-trained typically does not take as good care of their cutlery not to mention that most average home-owners either 1) flat out don't use their sharpening rod or 2) don't use it properly.
I only know what I've seen dealing with hundreds of home-owners in and around Chicago. Obviously someone who is more educated than your typical home-owner is going to get more use out of and take better care of their knives. I just believe in the less-hassle approach
hotdogg, regarding chefs and use of Cutco, I think I mentioned before that especially due to the way in which they are trained to hold a knife, most chef's find Cutco uncomfortable. I do know that there are chefs which use it however - Abbey Dodge, who is associated with Fine Cooking Magazine is the first person that comes to mind for me at the moment. Still, Cutco was designed with the average home-owner in mind, so if you're someone who is professionally trained, then things like the handle which was designed to make holding the knife easier and more comfortable for your average person are going to get in the way of how you do things.