Before you read any further, go and get your racket. Press your thumb hard into the middle of the string bed and push the main strings sideways. Let go. If they spring straight back into line, carry on playing. If they sit where you shoved them, or you can feel notches catching as they slide, the answer to the question in the title is: now, or near enough.
Most club players restring when a string snaps, which means most club players spend a good part of the year using a racket that stopped doing its job weeks earlier. Here is what happens to a string bed over its life, and how to catch it before it costs you matches.
Strings begin dying the day they go in
A string is under tension the moment it comes off the machine, and from that moment it is trying to get back to its original length. Tension loss starts immediately and is steepest in the first hours and days, before it settles into a slow, permanent drift downwards. This happens whether the racket is played with or sits in a cupboard.
Different materials fall at different rates. Polyester and co-polyester strings, the stiff ones most spin-heavy players use, lose tension quickly and go hard and lifeless well before they break. Multifilaments and natural gut hold their tension and feel better for longer, but tend to fray and snap rather than go quietly dead. Knowing which type is in your racket tells you which failure to watch for.
The old rule of thumb, and where it falls down
The traditional guide is simple enough to remember without writing it down: restring as many times per year as you play per week. Twice a week means twice a year. Four times a week means four restrings a year.
It is a decent floor, and it is a genuinely useful starting point for a club player. It also has obvious gaps. It ignores string type, so a polyester player should be restringing more often than the rule suggests. It ignores how hard you hit, and it ignores whether you are competing or knocking up socially. Use it as a minimum, then adjust upwards for anything that shortens string life.
The first fortnight
A fresh string bed plays at its best in the first couple of weeks, but it is also settling. If you have a tournament coming up, having the racket strung a few days beforehand rather than the night before lets that initial drop happen before it matters, so what you practise with is what you compete with.
This is also the window to notice what you actually have. If the racket feels uncontrollable straight after a restring, the tension was too low for you. If it feels boardy and dead from day one, it was too high. Say so next time. Two or three pounds either way is a small adjustment with a very noticeable result.
The long middle
After the settling period, tension drifts down slowly and quietly. This is where dead strings do their real damage, because nothing announces itself. The ball starts landing a little longer, so you take a bit off your swing without deciding to. Or the string bed goes stiff and short and you start swinging harder to get depth.
Either way, you have adjusted your technique to compensate for equipment. Players who restring on schedule rather than on breakage never have this conversation with themselves.
Three signs the string bed is finished
- You have lost control of depth. Balls that used to land inside the baseline are now sailing long, or dropping short, and you are steering rather than swinging.
- The strings are notched and stay out of line. Run a fingernail across the mains where they cross. Grooves you can feel mean the strings are sawing into each other and no longer snapping back, which is where your spin was coming from.
- The sound has gone flat. A live string bed has a crisp note at contact. A dead one gives a dull thud. Stringers diagnose half of these over the phone by the sound alone.
Add a fourth if your arm is talking to you. Dead polyester transmits more shock, and a stiff old string bed is a common cause of elbow niggles that people blame on the frame.
Broken strings are the easy case
When a string does snap, the decision is made for you. One practical thing to do straight away: cut the rest of the strings out. A frame left with half a string bed still under tension is loaded unevenly, and there is no reason to leave it that way while the racket waits its turn. Cut from the middle outwards so the load comes off evenly.
Then note where it broke. Snapping in the middle of the mains is normal wear. Breaking repeatedly near the frame at the top or the sides can point to something else, and it is worth mentioning when you hand the racket over.
Restringing is a chance to change something
A restring is the cheapest experiment in tennis. Before defaulting to the same string at the same tension, think about what you want the racket to do differently. Lower tension for more power and comfort, higher for more control. A thinner gauge for feel and bite, a thicker one for durability. A hybrid, with a tough string in the mains and something softer in the crosses, if you break strings but want your arm looked after.
Keep a note of what went in and at what tension, or ask us to keep it on file, so you are comparing rather than guessing. The range of tennis strings is large enough that changing blindly teaches you nothing. For what a particular job involves, ask in store and we will talk you through it with the racket in front of us.
Rackets that hibernate
Tension loss does not pause over the winter. A racket strung last August and left in a bag since October has lost tension without hitting a single ball, so the first outdoor session of the season is often played with strings that were finished months ago. If you play seasonally, book the restring before the season rather than three weeks into it.
Storage helps a little. Extremes of heat and cold both accelerate the decline, so a car boot through a Cardiff winter is about the worst place a racket can live. A thermal racket bag and a spot indoors will not stop tension loss, but it will slow it. And while the racket is out of the bag, look at the grip: a fresh overgrip costs very little and does more for your first session back than most people expect.