I bought a used racquet which came strung with Technifibre X-1 Biphase 17. I immediately played well with the racquet and, when the strings broke, i restrung with the same string and have continued playing well. I am a strong 4.0-4.5 player who was never much of a string breaker and suddenly these strings are lasting me a much shorter time than my old strings used to. I used to play with Prince "Hybrid" Syn Gut Poly Blend - which are 1/3 the price of the Technifibre strings, but don't know if the strings are the reason I am playing so much better or if it is the racquet. No one on this board mentions the TF X-1 Biphase 16. Would that help prevent breakage or is that string not as good as 17? I cannot afford to restring every few weeks, so if there is an alternative string which will give me enough, I would like to hear about it. Any thoughts? Thanks.