The most important contributor to a great performing racquet is the string you put in it. Some people do their racquets an injustice by not putting quality strings in.
After all, our strings are the only thing that touches the ball.
Some types of string lose tension faster than others, big or topspin hitters wear strings out much faster than flat hitters, and some players seem quite happy to let the strings decide when to be replaced -- by breaking.
2 x per week, 2 x per year
A simple rule of thumb: Restring your racquet as many times a year as you play, on average, in a week.
Listen
When you tap a strung frame against your hand, fresh strings will produce a resonant sound or "ping", while dead strings will produce a deep "thud". So if you don't hear a ping, it's time to restring.
Haven't played?
Even if you don't hit one shot, your racquet will lose tension. If you haven't played for a few months, you should restring. Even the perfect racquet won't perform if your strings have lost tension.
No control?
When your strings lose tension, you have less control. So missing that cross-court shot by four feet doesn't necessarily mean you are playing worse than you were last week. It could easily mean that your racquet needs new strings.
