I am between LeeD and the other "the racket doesn't matter" and the guys who change 4 times a year in search of the magic wand.
I demo before I buy. I buy 2 or 3 and customize to my spec. Then, I swing 'em for a couple of years until I get the bug for some new toys. The shortest period I have used a racket in recent memory is 1 year and the longest is 4 years.
LeeD, I don't see how you use such different specs interchangeably. I like to get 2 or 3 I like with the exact specs and then maybe tweak tension and that's it. To have a different weight, balance, SW, or beam size on each frame would drive me crazy.