For decades now, the adage has been to restring your racquet “as many times per year as you play per week”. Some time back, I had the opportunity to discuss this with the man who came up with it. Even he agrees now that this is not sufficient.
Since the phrase was coined, we’ve learned a lot about how strings react under use, and it’s not always pretty. Even gut strings -- which maintain playability longer than anything man-made -- will lose their tension and resilience, becoming inefficient for your game. Synthetic gut and, especially, polyester strings will do so much faster.
A good restringing schedule for most club players would be to replace gut strings after 50-60 hours of play, synthetic gut or multi-filaments after 40 hours of use, and polyester before 40 hours of playing time has elapsed. As a minimum.
I don’t have the exact numbers, but I’m quite confident that the average tennis player spends more money every year on coffee, beer, wine or ice cream than they do on strings. Rearrange the budget a little if you must, but do yourself and your game a favor by getting on a good stringing schedule.