Please now, let's not give the manufacturer's any more ideas with promoting new rackets. I'm no expert but my opinion would be yes, an older racket may flex a little more than a brand new one untouched. Especially if one has the tendency to flex the older racket with their hands often. To say that one needs a new racket because the current one changed stiffness so drastically, I do have a hard time believing it would happen. I think if one goes to a store and has a rack full of identical rackets, one will easily find differences in stiffness due to tolerances. Comparing a older used racket to a brand new one can also show a difference due to different batch material, tolerance, manufacturing, etc.