Initial loss
Some tension leaves early
Strings usually lose some tension soon after stringing, even before the first hit. That is normal and not just a playing-hours issue.
Reference Guide
Do Tennis Strings Lose Tension If You Don't Play?
Yes. Strings can lose tension even when the racket is sitting in the bag or closet. Playing accelerates wear, but time alone still changes how a stringbed feels.
Short Answer
Why unused strings still change
Ongoing change
Time still matters
As the string sits under tension in the frame, it continues to relax. That means a racket can feel older even if it has not been used much.
Material difference
Some strings age better than others
This is one reason material choice matters. Some string families keep their character better over time, while others feel noticeably different sooner.
What to Watch
How a stored racket can still feel different
Launch changes
The stringbed may feel looser or less predictable
Even without heavy use, the ball can start coming off differently as the setup relaxes over time.
Feel changes
It may feel older than the hours suggest
Players sometimes say, "But I barely used it." That can still be true while the stringbed no longer feels fresh.
Environment matters
Heat and storage conditions make it worse
A racket left in a hot car or unstable environment can age faster than one stored carefully, even with very little court time.
Practical Rule
Do not judge only by how many times you played
If it feels off
Trust the feel, not just the memory
If the racket feels stale, unpredictable, or harsher than expected, it may be time to restring even if you have not hit that much.
If you play infrequently
Time-based restringing still makes sense
For occasional players, a calendar-based check can be just as important as a playing-hours check.
Best habit
Think about age and use together
The best way to judge strings is with both variables in mind: how much you played and how long the setup has been sitting there.