You can't use "every" and "depending on use" in the same sentence, as that could be said of anything. I have a four year old cable of said type which, except for a little dust, is looking as good as new.
Were you to say that it occurs during average usage however, I agree that it would be an issue.
I read "depending on use" as a modifier to 2-3 years not on every. That is to say the cable will break sometime between 2-3 years with heavy use being sooner rather than later.
That's what I meant yes. Although I guess if you are really careful it would probably last longer. However the heat from the adapter (and the magsafe plug) will slowly degrade the rubber and glue.
The one I'm currently using is 6 years old. My boss had to replace his within a couple years and they showed him how to properly wrap the cable. He taught us and it's been fine.
Hey more anecdotes! I love my Air, it will be replaced with Airs until the patent on MagSafe runs out. That having been said, Apple's fray-prevention on all of their cords is nothing more than "pretty design". It certainly isn't functional or it would look like the same component on other cables... that... actually prevent the fraying in question.
Were you to say that it occurs during average usage however, I agree that it would be an issue.